Pale, Brown and Sad - what's my gameplan?

[timdanger]

First, get your own RO/DI. By using someone elses water you are not in control of nutrient import, you have given that to the person who monitors that water supply. If you suspect your salt then change brands to Tropic Marin

Second, why the DSB? Thats just a big nutrient trap in your sump. You were definaltely overfeeding and may still be. Having overfed your tank for an extended period you now have a nutrient rich sand bed that is going to continue leaching nutrients back into your system. Detritus has settled in it and will give you phosphate and nitrate problems. Phosphates bond to the ca carb based sand and will slowly leach it back in. If it were me I would turn off the pumps and totally remove the sand bed and throw it away. If you really feel you need it then wait until you have your tank dialed in and add some new sand back. Your other option is to change your GFO every week until you have no algae growth. But be prepared it may take months longer to get the nutrient levels down

i've definitely considered removing the DSB. i do have a question about what you're saying, though. you say detritus has settled in the DSB and is going to leach nutrients. the way i'm thinking of it, the only detritus would be from the turbo snail i occassionally put in there to clean up algae or organisms that live in the LR/LS. I don't feed the sump, only the display (which does not have a DSB). and, there is a filter sock that collects anything that drains into the sump from the overflow. Does that make a difference, or do you still see it as a nutrient trap?

And finally stability, corals are very tolerent of temp swingsbetween 75-82, but not tolerent at all of alk swings get that dialed in and your corals will be much happier. Sounds like you are close to getting that down but stay on it until you have it down pat.

my alk swings have actually continued, unfortunately. i've been at 6.5dkh for the last 10 days or so, despite adding extra Alk solution to bring that number up (beginning on 9/12, i dosed 40ml additional Alk solution beyond my 10ml/day Alk/Ca dosing, and it didn't even change my number over the course of the last 8 days). meanwhile, my Ca is up around 430. definitely having trouble keeping it stable, despite my best efforts.

 

[timdanger]

hm.. just came across this from a RHF reefkeeping magazine article (this one):

"If an aquarist is supplying a balanced additive to his aquarium, and calcium seems stable but alkalinity is declining, it may very well be that what is needed is more of the balanced additive, not just alkalinity. This scenario should be assumed as the most likely explanation for most aquarists who should look for more esoteric explanations for alkalinity decline only if calcium RISES substantially while alkalinity falls."

never occurred to me, but after reading this, it seems like i'm just not dosing enough of my 2-part solution.

 

[Ycore]

Dump the DSB, trust me. I had the same one and it did nothing beneficial and removing it cleaned up my algae problems big time. It also freed up room in my sump for other stuff.

Honestly get an RO/DI. They are so cheap and save you a major hassle of lugging water back to the store and you know the water has 0 TDS. My RO/DI and Apex aquacontroller I count as my two best investments.

Something is obviously very wrong considering the loss of coralline, the algae, and coral unhappiness. Time to mix it up IMHO and eliminate the possibilities. I think ditching the DSB and making your own water are good starts. I know people say good things about D&D salt, but for me things seemed to respond better to Tropic Marin. It also mixes a lot faster and is a finer grade salt.

 

[timdanger]

Dump the DSB, trust me. I had the same one and it did nothing beneficial and removing it cleaned up my algae problems big time. It also freed up room in my sump for other stuff.

Honestly get an RO/DI. They are so cheap and save you a major hassle of lugging water back to the store and you know the water has 0 TDS. My RO/DI and Apex aquacontroller I count as my two best investments.

Something is obviously very wrong considering the loss of coralline, the algae, and coral unhappiness. Time to mix it up IMHO and eliminate the possibilities. I think ditching the DSB and getting a guaranteed source of good water is a good start. I know people say good things about D&D salt, but for me things seemed to respond better to Tropic Marin. It also mixes a lot faster and is a finer grade salt.

re: the DSB, i am always thinking about removing it and then talking myself out of it for fear of crashing the tank. and, i mean, i do test at 0 nitrates/phosphates and always have. i'd hate to fix one problem by causing another.

re: the salt mix, i'm certainly open-minded about salt mixes. i obviously don't feel like i'm realizing any advantage by using the D-D, and for as much as it costs, that's hard to justify. the Ca for the D-D i get from the LFS consistently tests at 360ppm (per my Elos kit) at a salinity of 1.025 (per MD refractometer).

re: the RODI, i know it. it's a hard sell for my wife because she likes going to hang out and talk with the people that work at the LFS.

re: apex aquacontroller -- i'm thinking about one myself. will it make my life indescribably better?!

 

[RickMartin]

Alk is not just depleted by coral growth. Decaying organics release mild acids that cause the alk to drop. If you have a large build up, which I suspect you do, then this would be my guess as the problem. However by all means increase both of the 2 part additive, just keep an eye on the ca level.
I didn't notice the filter sock, although I doubt if it caught all your detritus. Lose the filter sock as well. Having a filter sock is the equivalent of routing your air conditioning intake vent through your sewer line. Even if you clean the sewer line every week its still going to stink. Essentially you are forcing all the water in your tank through all that decaying material, forcing it to break down

 

[RickMartin]

Lose that phosphate test, worthless. If you have algae problems you have excess nutrients period

 

[Ycore]

I had the same worry concerning removing my DBS. The only two potential causes of a crash imho can come by:

1) Removing the DBS releases hydrogen sulfide gas or other toxins and crashes the tank. For me, this was easily mitigated. Turned off pumps, used some wedges of foam in the baffles to 100% segregate the middle compartment in the sump from the other two compartments (just as precaution in case mud or gunk flew around as I vacuumed out the sand) and used a shop-vac to hoover it all out. Rinsed it down a few times with ro/di water, revaced, and the DSB was all gone and the compartment sparkling clean.

2) Crash because you think the DSB is acting as a significant denitrator and you'll get a nitrate or ammonia spike.. Not likely based on the DSB size and what seems like a low bioload in your tank.

BTW, I also found D&D to test low for calcium and Mg..

I agree with the useless phosphate tests.. Only thing accurate is a Hanna meter. But honestly, the rpesense of algae is the best phosphate test out there.

I don't agree on removing the filter sock though.. I got tired of chnaging mine out every few days and the yucky laundry duty they entailed, but within a few weeks my sump was nasty with detritus and my sandbed was getting yucky. I agree that the sock works against you if you let stuff get to the point where it rots, but if you change it out a few times a week it's not a problem. Even then, I'd kinda rather have it rotting in my sock than rotting all over my sump.


As for the Apex controller, it's not something that will make your tank happy again, it's just something that to me is a major security blanket and automates all sorts of stuff. It automates my dosing, my top off, regulates my heaters, monitors pH, sends me an email when all sorts of things are out fo whack, like if I forget to turn my vortech back on after feeding, if my ATO is on for more than 10 minutes, if my Ph goes outside a desired range, etc.. Best of all, I can control every single device on my tank from my Iphone.. When I realized that I had forgotten to turn my vortech back on after feeding in the morning, I was able to do so from on the road direct from my phone..

re: the DSB, i am always thinking about removing it and then talking myself out of it for fear of crashing the tank. and, i mean, i do test at 0 nitrates/phosphates and always have. i'd hate to fix one problem by causing another.

re: the salt mix, i'm certainly open-minded about salt mixes. i obviously don't feel like i'm realizing any advantage by using the D-D, and for as much as it costs, that's hard to justify. the Ca for the D-D i get from the LFS consistently tests at 360ppm (per my Elos kit) at a salinity of 1.025 (per MD refractometer).

re: the RODI, i know it. it's a hard sell for my wife because she likes going to hang out and talk with the people that work at the LFS.

re: apex aquacontroller -- i'm thinking about one myself. will it make my life indescribably better?!

 

[timdanger]

Alk is not just depleted by coral growth. Decaying organics release mild acids that cause the alk to drop. If you have a large build up, which I suspect you do, then this would be my guess as the problem. However by all means increase both of the 2 part additive, just keep an eye on the ca level.

my understanding from Randy's articles about Alk depletion via decaying organics is that, while alk is depleted as the nitrogen cycle produces nitrate, the subsequent conversion of nitrate to n2/etc. releases that alk back into the water. so, as long as i'm not building up nitrates (which it doesn't appear that i am since my nitrates consistently test at 0ppm, which either means that the nitrates are being converted to n2/etc. and/or that the nitrates are getting converted by algae/other organisms). thoughts?

I didn't notice the filter sock, although I doubt if it caught all your detritus. Lose the filter sock as well. Having a filter sock is the equivalent of routing your air conditioning intake vent through your sewer line. Even if you clean the sewer line every week its still going to stink. Essentially you are forcing all the water in your tank through all that decaying material, forcing it to break down

as far as the filter sock goes, it is there primarily to reduce noise from my drain line (which is important, as this tank is in my bedroom). i have 4 filter socks that i regularly rotate between. i certainly acknowledge that there are advantages to eliminating the filter sock, but i also don't know that i could live without it. that, and i think there are advantages to keeping the filter sock there (e.g. immediate export of algae/trapped detritus/other organics that therefore don't have to break down in the tank).


what about the concept of making flow more efficient to help get detritus into the water column (and eventually into the filter sock and out of the tank)? My thoughts are:
1) reposition the tunze 6025 so that it's flowing in the same direction as the vortech mp10, creating more of a gyre and less of a "collision" of water that may end up neutralizing some of the current.

2) remove 2 of the big rocks in the display (middle rock in the left tier, bottom rock on the right tier). this will pull my corals deeper into the tank, so less light (maybe switch back to a 14k bulb from the radium?), but it will also improve my flow dramatically. that should help keep some of the junk in the tank from settling too much.

i also plan to remove the live rock rubble from the first chamber of the sump.

 

[timdanger]

Lose that phosphate test, worthless. If you have algae problems you have excess nutrients period

agreed -- not my test, i just had the LFS test my water to check my Mg, and they ran a full water test.

 

[timdanger]

2) Crash because you think the DSB is acting as a significant denitrator and you'll get a nitrate or ammonia spike.. Not likely based on the DSB size and what seems like a low bioload in your tank.

this is more a concern than the hydrogen sulfide one. i feel confident that the cad baffles would allow me to segregate that compartment and get rid of the problem

Best of all, I can control every single device on my tank from my Iphone.. When I realized that I had forgotten to turn my vortech back on after feeding in the morning, I was able to do so from on the road direct from my phone..

sounds life-changing to me. i am out of town too much, and i really need to know when stuff screws up.

i have a droid 2; i heard there was an app for it, but i haven't actually looked for one.

 

[Ycore]

I think it has been proven that unless you have a DSB with a large surface area, any amount of denitration it provides is minimal. This is one of the reasons I got rid of mine. Certainly removing mine didn't spike nitrates/phosphates at all.

There is a Droid app for the Apex, so you're good there. For me the Apex is a huge automater and security blanket. It makes everything a one button routine. For instance, this is my coral feed program. It's all one button on my Iphone. When I press it the following occurs:

1) Shuts down return pump, turns off vortechs, stops skimmer, deactivates sensor for high sump level, turns off top/off system. Feed tank.
2) 20 minutes later vortechs come on at 10% constant speed to swish food around tank
3) 40 minutes later vortechs are adjusted to 50% nutrient transport mode
4) 60 minutes later return pump comes back on
5) 65 minutes later skimmer comes back on after sump level has stabilised. auto top off system reactivated.

All this takes is one button push. I can feed my tank and leave and everything else is automated.

this is more a concern than the hydrogen sulfide one. i feel confident that the cad baffles would allow me to segregate that compartment and get rid of the problem



sounds life-changing to me. i am out of town too much, and i really need to know when stuff screws up.

i have a droid 2; i heard there was an app for it, but i haven't actually looked for one.

 

[ArtemisGoldfish]

this is more a concern than the hydrogen sulfide one. i feel confident that the cad baffles would allow me to segregate that compartment and get rid of the problem



sounds life-changing to me. i am out of town too much, and i really need to know when stuff screws up.

i have a droid 2; i heard there was an app for it, but i haven't actually looked for one.

I also say get rid of the DSB. Just as an example, I was using a DSB refugium in a 65g sump for my 180. I noticed overtime that the refugium became a cesspool of nutrients. This was acting as fuel for my Cyano problem. I scrapped the DSB as a result. It was time consuming as I had to get under the tank, but well worth it. Just turn off the return and intake to the sump and scoop it out. Try not to do it in an enclosed area. Sulfur dioxide will irritate your sinuses.

I'd also recommend an algae scrubber. I use one and it works well for removing phosphates, nitrates and ammonia. It's self sufficient for the most part too once you set it up.

Also, I am without a doubt certain that you have a flow issue (too little).

One thing to keep in mind with corals is that we only notice an issue after significant tissue damage or recession has occurred. Consequently we wrack our brains and attempt to throw everything we know at the problem. After you address general stability issues, relax and let go. Any positive headway that will be made is going to take a few weeks to show.

 

[RickMartin]

my understanding from Randy's articles about Alk depletion via decaying organics is that, while alk is depleted as the nitrogen cycle produces nitrate, the subsequent conversion of nitrate to n2/etc. releases that alk back into the water. so, as long as i'm not building up nitrates (which it doesn't appear that i am since my nitrates consistently test at 0ppm, which either means that the nitrates are being converted to n2/etc. and/or that the nitrates are getting converted by algae/other organisms). thoughts?

Alkalinity is constantly depleted even in fish only systems. I am not sure what you are thinking but thats how it is.

You have good advise and don't seem to want to follow it. Wait long enough someone will give you the answer you want, even if it's the wrong one.

Good luck

 

[timdanger]

Alkalinity is constantly depleted even in fish only systems. I am not sure what you are thinking but thats how it is.

You have good advise and don't seem to want to follow it. Wait long enough someone will give you the answer you want, even if it's the wrong one.

Good luck

i'm not trying to ignore good advice or pick and choose advice. i'm just trying to address the things i've already thought about in a constructive discussion. just because i disagree with something or ask about something doesn't mean i'm being disagreeable or obstinate. i'm just trying to understand what's happening.

i agree that alkalinity is depleted in fish only systems, but i would suggest that this kind of depletion is not only due to the accumulation of nitrates as a result of decaying organisms (nitrification), but also as a result of, for instance, the growth of coralline algae and use by other calcifying organisms, etc. also, you saying that alkalinity is depleted "even in a fish-only system" ignores what i said my understanding is (per Randy Holmes-Farley) about alkalinity being consumed when nitrates accumulate in the system but released when nitrate is converted to n2/etc. - that happens whether we're talking about fish-only or reef systems.

 

[timdanger]

this article is where RHF says: "One of the best known chemical cycles in aquaria is the nitrogen cycle. In it, ammonia excreted by fish and other organisms is converted into nitrate. This conversion produces acid, H+ (or uses alkalinity depending on how one chooses to look at it) . . . For each ammonia molecule converted into nitrate, one hydrogen ion (H+) is produced. If nitrate is allowed to accumulate to 50 ppm, the addition of this acid will deplete 0.8 meq/L (2.3 dKH) of alkalinity. However, the news is not all bad. When this nitrate proceeds further along the nitrogen cycle, depleted alkalinity is returned in exactly the amount lost. It turns out that as long as the nitrate concentration is stable, regardless of its actual value, there is no ongoing net depletion of alkalinity. Of course, alkalinity was depleted to reach that value, but once it stabilizes, there is no continuing alkalinity depletion because the export processes described above are exactly balancing the depletion from nitrification (the conversion of ammonia to nitrate)."

To your point, RHF does say: "There are, however, circumstances where the alkalinity is lost in the conversion of ammonia to nitrate, and is never returned. The most likely scenario to be important in reef aquaria is when nitrate is removed through water changes. In that case, each water change takes out some nitrate, and if the system produces nitrate to get back to some stable level, the alkalinity again becomes depleted. If, for example, nitrate averages 50 ppm at each water change, then over the course of a year with 10 water changes of 20% each, the alkalinity will be depleted by 1.6 meq/L (4.5 dKH) over the course of that entire time period. This process is one of the primary reasons that fish-only aquaria that often export nitrate in water changes need occasional buffer additions to replace that depleted alkalinity."

But, after summarizing the process, RHF says Consequently, while this effect of nitrate production on alkalinity is enough to be noticed over the course of a year, it is substantially smaller than the other effects discussed in this article, and is unimportant for aquaria that maintain low nitrate levels."

 

[RickMartin]

What is your point? You are quoting something that says itself has little if any overall affect on Alk. You don't really have a Alkalinity problem? Or are you not aware of other processes in the aquarium that deplete it? Like the release of CO2 by plants and animals and decaying organic matter.
For that matter since ammonia is the preferred nitrogen source for algae (Lobban and Harrison, 1994). You nitrogen cycle is probably totally hijacked

 

[Ycore]

I don't think Alk is your problem. Test it in the morning. Test it in the evening. If it doesn't vary by 1-2 dKh then Alk isn't your problem. If it does, drip kalk or mix alk into your topoff water. However, Alk swings cause STN. Your problem is "pale, brown, and sad"-- with a slow decline in color and health. Ditch the DSB, get water you cna trust. If you insist on getting water at the LFS, invest $20 and get a TDS so you can make sure it is 0 TDS. I guarantee you your problem isn't dosing, and if it is, it's because your dosing too much. You don't have huge colonies of SPS or clams,

To me your problem looks like nutrients. Your algae is just way out of control.

If I were you:
1) remove DSB
2) send water sample to aquariumwatertesting.com
3) get ro/di or at least a TDS meter to test LFS water
3) if your tunze is really not pumping water and you're only getting a trickle, then obviously this is a problem. Fix or replace.
4) Increase Ferric Oxide or run biopellets in your reactor

 

[ryanjiang]

You have good advise and don't seem to want to follow it. Wait long enough someone will give you the answer you want, even if it's the wrong one.

Good luck

I would agree RickMartin on the comment, plus you are asking for suggestions/advice, there is no point to debate. Even you do not with somone's point, does it harm by just return a warm thank note and something like 'you make a point', or 'I will consider this', just make people feel good and get encouragement to jump in & help others more.

Now I have stopped posting thoughts/recomendations, on one side when I see some postings with frustrations and desire to get things fixed, I want to jump in and help. But in many many cases, your suggestions are not appreciated or totally ignored. Everyone's time is precious, now I would rather save my time to study someone's succussful reef and try to learn from there.

* I have posted earlier in this thread, I don't think this is a nutirent issue here, we saw SPS strive & have good coloration in ULN or little 'dirty' water with 20 or 30 PPM NO3. Even it is indeed a nutrient issue, 1st thing 1st you should stabilize important parameters such as CA, ALK, MG and act from there.

 

[timdanger]

What is your point? You are quoting something that says itself has little if any overall affect on Alk. You don't really have a Alkalinity problem? Or are you not aware of other processes in the aquarium that deplete it? Like the release of CO2 by plants and animals and decaying organic matter.

I'm not sure I understand how what you're saying relates to the quoted part of the article. I quoted the article in response to you saying that "decaying organics release acids that cause the alk to drop" -- are you talking about something other than the acid produced in the breakdown of organics via the nitrogen cycle? I assumed this is what you were talking about. To that point, the RHF article says: "One of the best known chemical cycles in aquaria is the nitrogen cycle. In it, ammonia excreted by fish and other organisms is converted into nitrate. This conversion produces acid, H+ (or uses alkalinity depending on how one chooses to look at it), as shown in equation 1: NH3 + 2O2 --> NO3- + H+ + H2O"

The article is saying, contrary to what you suggested, that a completed nitrogen cycle (i.e. not just a buildup of nitrate) doesn't have an effect on alkalinity except to the extent that nitrate is removed by water changes. I certainly never suggested that the coral calcification were the only processes that deplete alkalinity.

Am I misunderstanding you? If you're disagreeing with RHF, I'm not saying that you're wrong or anything, but you'd be talking over my head and I'd be happy to see you two talk about that.

For that matter since ammonia is the preferred nitrogen source for algae (Lobban and Harrison, 1994). You nitrogen cycle is probably totally hijacked

That is interesting information that I didn't previously know, but my tank isn't overrun with algae, as you can see in my pictures. It just has a few small outbreaks here and there. To say my nitrogen cycle is "probably totally hijacked" seems like a bit of an exaggeration.

I would agree RickMartin on the comment, plus you are asking for suggestions/advice, there is no point to debate. Even you do not with somone's point, does it harm by just return a warm thank note and something like 'you make a point', or 'I will consider this', just make people feel good and get encouragement to jump in & help others more.

Now I have stopped posting thoughts/recomendations, on one side when I see some postings with frustrations and desire to get things fixed, I want to jump in and help. But in many many cases, your suggestions are not appreciated or totally ignored. Everyone's time is precious, now I would rather save my time to study someone's succussful reef and try to learn from there.

* I have posted earlier in this thread, I don't think this is a nutirent issue here, we saw SPS strive & have good coloration in ULN or little 'dirty' water with 20 or 30 PPM NO3. Even it is indeed a nutrient issue, 1st thing 1st you should stabilize important parameters such as CA, ALK, MG and act from there.

I do agree that I have gotten advice that I haven't taken. It's not that I don't appreciate the input, but it's hardly fair to criticize me for that when I get conflicting advice and can only follow one side or the other! And, this is the internet -- not everyone's advice is good, and not everyone's advice makes sense. For instance, you don't think it's a nutrient issue, but RickMartin says "If you have algae problems you have excess nutrients period." Which of you should I believe? Based on my own experience with treating this, and my own research and judgment, I believe RickMartin is right when he says I have excess nutrients. Now, that may not be the only issue, but I believe it's at least one.

If someone says something that I think goes against something I understand from a book or article by experts in the field, I might want to discuss (not debate) it with them to make sure that I understand. For instance, it may be that I have misread or misunderstood the article. This is what is happening with RickMartin. I am simply quoting from the RHF article so he sees what I'm talking about. Now, in this case, I do not believe I am misunderstanding the article, so I continue the discussion. If the discussion is unproductive, I will suggest we agree to disagree.

As far as your points go:
1) I do agree that I need to get Ca/Alk/Mg locked in better. No question there. It's really only about a 1.5-2dkh (0.5meg/l) swing that happens in Alk -- the Ca is pretty stable, and the Mg, though lower than i'd prefer, isn't so low that it should be a definitive cause of this issue. I thought I had it locked in better than I did, but based on the RHF article that I read, it seems clear that I need to increase my 2-part dosing. Maybe that will take care of some of my issues (keep in mind, my issues are not RTN/STN -- I haven't had any of that. Only drab colors and algae), but you can't point to Alk instability to being the cause of my cyano issues, can you? Or, can you?

2) I understand that people have had success with SPS even with nitrate up to 20-30ppm. However, remember that I already tried (over the course of at least 3 months) adding AquaVitro, Roti-Feast, increasing feedings, decreasing changes of carbon/gfo, decreasing water changes, and all that did was lead to an influx of algae. no effect on coral coloration. So, it's not fair to say that I ignored this advice on this issue.

The only advice I have not yet taken is 1) removal of DSB; and 2) RODI unit. However, that's not for lack of consideration. I've just discussed my concern with removing the DSB, and with the RODI unit, it's just a budget issue (had to get the dosing pumps first because I thought it was more important to keep Ca/Alk stable rather than worry about potentially introducing nutrients into the water via LFS water).

 

[timdanger]

I don't think Alk is your problem. Test it in the morning. Test it in the evening. If it doesn't vary by 1-2 dKh then Alk isn't your problem. If it does, drip kalk or mix alk into your topoff water.

i'm not getting that kind of alk swing during the day. my alk swings take place over the course of a week or 10 days. i'm adding 10ml/day Ca/Alk via my dosing pumps. Based on a rough estimation of my total water system volume, I calculated that I need to add ~28ml of my Alk solution to raise my Alk by 1dkh. So, if I didn't dose for 3 days, my Alk would drop by a little more than 1dkh. Let's just say that my Alk is dropping by 2kh over the course of 10 days. That means I'd be under-dosing by ~6ml/day. a 6ml/day increase in my 2-part dosing (bringing me to 16ml/day) isn't outlandish, given the amount of stony corals, live rock, inverts and macroalgae (including coralline) in my tank. Thoughts?

To me your problem looks like nutrients. Your algae is just way out of control.

i think you're probably right. it should be noted, however, that the chaeto in my sump has almost completely stopped growing (prior to adding my GFO reactor, i was having to prune it almost weekly).

If I were you:
1) remove DSB
2) send water sample to aquariumwatertesting.com
3) get ro/di or at least a TDS meter to test LFS water
3) if your tunze is really not pumping water and you're only getting a trickle, then obviously this is a problem. Fix or replace.
4) Increase Ferric Oxide or run biopellets in your reactor

i think i'm finally on-board with removing the DSB. i might as well try it, and i can certainly get by without it.

that aquariumwatertesting.com website is interesting. i'm going to keep that in mind if my first set of changes doesn't fix things.

i'll talk to the wife abou tthe RODI.

i am concerned about my tunze. i might actually call tunze usa and ask about that.

i've thought about those biopellets. i go back and forth on those. for now, i'm running my GFO reactor about 1/4 full, changing out (or just adding) every 3-4 weeks.