Calcium Reactor Settings

[rwessels]

I have never been able to keep up with my Ca/Alk requirements so by posting my numbers, maybe I can at least be steered in the right direction. My tank is about 360 gallons in total water volume. The tank is 300 gallons of that and is moderately stocked with SPS and one 7" clam. PH of the tank runs from 8.1 to 8.2.

Numbers I am shooting for:

3.5 meg/l Alk
420 Ca

Current Equipment:

MRC CCR-818 Single Stage Reactor
20 Lbs. Arm Media (filled to the top)
Pinpoint PH Controller attached at the exit point of the Reactor
Maxi-Jet 600 Feed Powerhead

I have tried PH levels from 6.0 to 7.0 and it does not seem to matter much. The highest I seem to get the output up to is about 7 meg/l, but that was at 50 ml/min out and a PH of 6.0. I had a few media meltdowns and I think it was because the PH was way too low. Currently I am running the output at 180 ml/min (most I can with the Maxijet 600) and the PH at 6.85, but my numbers are falling far short. The output of the reactor is less than 5 meg/l. The Alk in the tank will drop from 3.5 meg/l to 3.1 meg/l in 24 hours at which point I have to dose about 10 tsp of baking soda and 8.5 tsp of Pool Calcium (separately) in about 1 quart of RO/DI water.

I am dosing every day to keep the Alk up, but there has to be something I am doing wrong. This is one of the bigger reactors that I can get and I have seen reefers with far more SPS get away with smaller reactors without having to dose. So if someone can see the magic thing I am missing and wants to share, that would be great. If not, can I get:

1. A recommended PH level to set the reactor at.
2. What Alk level should I see on the output of the reactor?
3. Is 180 ml/min too much to put through this or should I bump up the powerhead and shoot for something like 300?

Thanks for any help!

 

[HDAlien]

Just getting my own reactor set up, but here's a bump because I'd like to see suggestions.

 

[Henry Bowman]

I'd shoot for a pH of 6.5 or maybe a 6.4 A pH below 6.4 is going to cause the media to "melt down" as you put it. You should get a dKh reading from the effluent in the 13-15 range.

Pushing more water through the reactor is going to be directly reflective of keeping the pH down low enough to melt the media.

Sounds like you may be approaching the limit of what your reactor can produce.

You should use this calculator to help adjust the reactor.

http://home.comcast.net/~jdieck1/chem_calc3.html

and this information (HD Alien) to help with set up

http://home.comcast.net/~jdieck1/reactor.html

Both articles / pages are written by very knowledgable RC member(s) and should help.


HTH

 

[rwessels]

Hmmm, I can't believe a reactor with 20 lbs of media is reaching a limit on a moderately stocked 300. I just can't seem to get the effluent up to where I think it needs to be - OR maybe there is something else besides corals that is using my ALK. My consumption according to the calculators is about 1 meg/l a day. Does that seem like too much?

Also, you said the effluent should be 13-15 - or about 4.6 to 5.3 meg/l. I would have expected that to be higher. I could have sworn people have said on other message they were getting like 25-30.

 

[Henry Bowman]

I may be wrong about the alk output. I dont think that you'll get it up to 25 without using a fluidized reactor like a deltec. You would probably get alot more responses if you posted this in the Reef Chemistry forum. Most of the Ca reactor tuning answers given there are much more detailed and thouough (than I can provide)

 

[Paulairduck]

I see no problem with that size of a reactor on a 300. You should shoot for an effluent of at least 24 dkh, you want three times in your effluent, than in the tank. Are you using the coarse arm media? I would doublecheck my test kits, because running a PH that low, should deffinitely give you higher numbers.

 

[wife no likey]

slow down your effluent. .this will allow for greater dwell time and should provide an increase in your output.

Pete

 

[besl]

I don't think I understand your approach in the original post - if I read this right you started with a drip rate of 50 ml/min, felt the alk was too low and adjusted this to 180 ml/min. Increasing drip rate should decrease alk, the opposite effect of what you wanted. So you have 3 variables to adjust: bpm of CO2, drip rate of effluent and pH of chamber. Recognizing you should keep the chamber pH above 6.0 (and more like 6.3 - 6.4 in your case) to avoid a media melt down, now your left with drip rate and bpm (which I didn't see mentioned above). I would get the drip rate back to 50 ml/min and bpm at around 40 - 50 bpm. Wait a day or two, measure alk and Ca. Reduce drip rate or increase bpm to increase alk or vice versa if alk is too high.

 

[rwessels]

Sorry in advance for the long post.

Maybe I missed part of my explaination. I started at 50 ml/min and lowered my ph as much as I could. I never saw the alk go up above 7-8 meg/l and at the 50 ml/min rate, would not be enough for the tank. I then proceeded to raise the rate and increase the amount of co2 to keep the ph low. My hope was to keep the alk going out at 7-8 meg/l, but increase the flow rate through the reactor. Unfortunately what happened, is the flow rate went up, the co2 usage went up, the ph stayed the same, but the alk going out went down. Everntually I lowered the PH even more, but in the end, the alk still stayed fairly low and I ended up with a media meltdown. This was all done on a prior reactor that was much smaller (held only 7 lbs of media).

I figured at that point, my reactor was too small and bought a commercial grade one that should have far more capacity than I needed. Too bad I am getting the EXACT same results.

Fast forward to the last few weeks. I emptied the reactor and put in all new media. I read somewhere that as long as you have the PH below 7.0, it will start adding alk. So I set the reactor at 6.9 and let it run for a few weeks. I noticed I was having to add a ton of baking soda (and ca) each day to keep the talk alk at 3.5. I would measure in the morning and get 2.8 - 3.0 and have to dose to get it back to 3.5. The next day I would be in the same spot.

Last night I decided to measure the alk coming out of the reactor - it was only 3.4. Obviously I need to crank the PH down a bit more. Based on the responses to my post so far, I have lowered the mid point on my pinpoint controller to 6.6. Tonight I will measure the alk coming out and possibly make furthur adjustments. I still have the flow at 180 ml/m so the bpm required to keep the PH that low is way to high to count. If I had to guess I think it would be in the 300-500 bpm range. Even with this much co2 being used, the net effect on the tank is only about .1. If tonight it doesn't look like I am getting a strong alk production, I will go ahead and lower the flow to about 100 meg/l and drop the PH another .1 in the reactor.

To summarize my lengthy post, I believe I fully understand how it SHOULD work. It is just that in practical use, it isn't working correctly for me.

 

[miwoodar]

<a href=showthread.php?s=&postid=10457309#post10457309 target=_blank>Originally posted</a> by Paulairduck
I see no problem with that size of a reactor on a 300. You should shoot for an effluent of at least 24 dkh, you want three times in your effluent, than in the tank. Are you using the coarse arm media? I would doublecheck my test kits, because running a PH that low, should deffinitely give you higher numbers.

I would tend to agree with this guy.

What is your magnesium level? Low mag can mess with your calcium and alkalinity.

 

[rwessels]

I will recheck all values including Mag tonight. Last time I checked it was like 1400.

 

[xinumaster]

At that drip rate your CA and ALK still reads low I would check your parameter again using a different brand of test kit. What test kit did you used?

I remember when I had a ALK reading of 3dkh using selifert I starting dumping baking soda to raise my ALK. But when I tested the alk again the alk is still at 3dkh so I suspected my test kit might be bad. I then bought an ELOS alk test kit and it reads 18dkh this time. Now I have to do a lot of water change to bring down my alk.

 

[rwessels]

Salifert. I am on my 3rd kit now as I am testing about once a day (twice when I am testing the effluent). I guess it wouldn't hurt to pick up a different brand to compare.

 

[xinumaster]

Of all brand of test kit I had used. ELOS is the best and easiest one to use.

 

[miwoodar]

I don't want to ask a stupid question but - where are you getting the water that you are testing? We are definitely talking about calcium reactor effluent here, right? I've never tried ELOS but Salifert kits aren't junk. If this is your third kit and you're still getting such low readings we are all overlooking something obvious.

Where did you pick up the media? Are you sure it's not freshwater aquarium gravel?

Are you doing the low accuracy test? If you are, are you multiplying by two? I've been guilty of this error a time or two.

If you don't have a good tracking sheet download dragonslayer's instructions and tracking sheet from this thread. I found it very helpful when I first set up my reactor.

http://reefcentral.com/forums/showthread.php?s=&threadid=334587

 

[xinumaster]

<a href=showthread.php?s=&postid=10462591#post10462591 target=_blank>Originally posted</a> by miwoodar

I've never tried ELOS but Salifert kits aren't junk.

You are twisting what I wrote. Sorry, but I never mentioned Selifert kits are junk.

 

[rwessels]

Valid questions - I am getting the test water from the reactor effluent. I didn't have much time to mess with things yesterday so I just lowered the PH on the controller to about 6.6 that morning. I have not lowered the flow yet. The good news is that my effluent measured about 6.5. I am using the low accuracy test for the effluent test. 2 cc's of water, 1 drop of the blue stuff and then multiplying my number on the sheet by 2. From a starting point 3.5 yesterday morning, I was at 3.4 today which is the lowest drop I have ever seen.

I am going to keep the PH at 6.6 and lower the flow to about 100 ml/min. I am hoping that the increased contact time will help further increase the alk in the effluent and offset the fact that I will be lowering the rate of flow through the reactor.

 

[miwoodar]

<a href=showthread.php?s=&postid=10462796#post10462796 target=_blank>Originally posted</a> by xinumaster
You are twisting what I wrote. Sorry, but I never mentioned Selifert kits are junk.

Apologies xinumaster - that wasn't the intent at all. I was not trying to imply anything along those lines. I just didn't want the OP to go out and replace perfectly good test kits.

To the OP - I'm baffled. I can't imagine getting such a low alk from my reactor. I'm getting almost twice the dkh you are and I run mine between pH of 6.7 and 6.8.

 

[jtravis2]

<a href=showthread.php?s=&postid=10462591#post10462591 target=_blank>Originally posted</a> by miwoodar
I don't want to ask a stupid question but - where are you getting the water that you are testing? We are definitely talking about calcium reactor effluent here, right? I've never tried ELOS but Salifert kits aren't junk. If this is your third kit and you're still getting such low readings we are all overlooking something obvious.

Where did you pick up the media? Are you sure it's not freshwater aquarium gravel?

Are you doing the low accuracy test? If you are, are you multiplying by two? I've been guilty of this error a time or two.

If you don't have a good tracking sheet download dragonslayer's instructions and tracking sheet from this thread. I found it very helpful when I first set up my reactor.

http://reefcentral.com/forums/showthread.php?s=&threadid=334587

Just for clarification he didn't say they were junk, he said "Salifert kits aren't junk".aren't

 

[miwoodar]

jtravis2 - you might have better luck if you have this thread transferred to the chemistry forum.