Help please! Alk monitoring - or Ca monitoring as an alternative

[zzz111]

First i'd like to thank reef central, Randy and all the reefers here, I've learnt a lot from you, although i almost never post.

I've been searching for an alk monitoring solution, something like you can stick a ph probe in water and read it anytime by looking at it, or on iphone through a webcam, or hook it to a tank controller to maybe take action in case needed. Do you guys know of any thing similar for alk? I can't seem find one.

The next best thing I found is a Ca monitor from Pinpoint, with AC adaptor it can be used for online monitoring. Sounds to me if Ca and Alk are normally in sync, given the balanced correspondence I know between Ca/Alk in my tank, I should be able to derive Alk from Ca readings, theoretically that is. But the problem is while I'm getting pretty repeatable alk readings (within 1-2ppm on repetitive tests, accurate or not who knows and we're hobbyists) from Hanna eggs on Alk, Hanna egg's Ca readings are usually all over the place, making a 10-20ppm variance quite happily swallowed, largely thanks to the rocket science 0.1ml measurement required by Hanna egg (I actually ordered a rocket science 100ul pipette and will see if that helps). So the question is how well does the Pinpoint Ca monitor work? Looking at the 20ppm Alk to 8ppm Ca correspondence, if I want a alk estimation within 5ppm accuracy from Ca readings, the Ca accuracy should be within 2ppm, is that something we can expect from the Pinpoint Ca? Asking because my Pinpoint conductivity sensor roams randomly between 48mS to 52mS in my 1.026-1.027 water, so it's totally useless, for salinity monitoring, not sure if the Ca monitor does any better.

Searched a lot before posting, and didn't find anything. I'm actually searching for an integrated tank controller, looking at ProfiLux at the moment. The thing is I already have things like top off, water change, lighting and dosing automated and 2 webcams staring at my tank, aside from the fun factor and disaster alarm, what else can an expensive controller add to the value. Alk monitoring and controlled supplement of Ca/Alk dosing would be the best reason to justify that new toy.

Thanks a lot in advance for any idea on alk or ca monitoring. Water change and tank noise had been my biggest headaches with the tank, now them been dealt with, alk automation becomes THE focus, as alk consumption does change and tank mates are not so tolerant to alk swing, to make it worse they're not that outspoken and when they do cry out it's usually too late to measure alk. I really need some techy stuff to take care of alk for me.

 

[MarcWeaver]

I am unaware of any monitoring probe for alkalinity, but I really wish there was one.

In my opinion, as well as many others, alk monitoring and stability is first and foremost. Calcium is treated as secondary, but not necessarily of unequal importance. In my tank for example, once alkalinity drifts too high or too low, my corals show me what is happening right away (as well as testing) but calcium can be all over the place with no ill effect on coral until it drops way low. I'm not sure what happens when it gets too high, but I have read accounts of 500-600ppm with no ill effects to coral. Plus, in an automated dosing situation, if your pumps go out of whack it takes much more calcium supplement to cause problems that it does alk supplement.

I don't believe that deriving alkalinity measurements from calcium numbers is the way to go, but that's just my opinion. Natural balance of alk and calcium is not always automatic. Check out this article and look at the tables when alkalinity and calcium are dosed in a balanced way but both are over or underdosed. In the second chart, over 7 days, calcium is at 470, but alk is at 15dkH. That will burn the tips of acros quickly, even before the alk gets close to 15, but calcium is not that far out of range. In a low-nutrient environment, an alk rise from 8 to 9 dKH in 12 hours can cause tip burn on acropora, I've done it.

http://reefkeeping.com/issues/2004-12/rhf/index.php

If I were you, I would set up dosing pumps or a calcium reactor if you don't have one or the other already, find your daily alk consumption and the mL of dosing it takes to keep it steady, then dose alk and calcium at the same rate and check once a week or so. Alk demand ebbs and flows, but should mostly go up or stay the same. A decreased alk consumption rate (your alk level keeps rising quickly while dosing despite usually being consistent over time) usually indicates a problem or can happen when replacing bulbs, GFO, or anything that temporarily shocks coral reducing its growth.

 

[bertoni]

I agree that it's difficult to track alkalinity using the calcium numbers, due to accuracy limitations. I don't think that the calcium probe will work as a monitor, either. There's a review of it here:

http://reefkeeping.com/issues/2005-04/rhf/index.htm

It's possible to automate alkalinity testing by using an auto-titrator setup, but there's no commercial product available to do that. It'd likely be rather expensive, in any case.

 

[zzz111]

Thanks Marc for your reply.

Yes I think too that Alk is the foremost thing I need online monitoring and regulation. I do have dosing pumps for limewater, salt water and saturated Ca acetate solution. I call it "blind dosing" since there's no closed loop control with feedback and auto adjustment based on monitoring.

Blind dosing kalk and salt water for top off and water change works fine over the past year and a half for me in terms of salinity, it's always within 1.025 and 1.027 whenever I checked although I seldom check it. But fixed blind dosing doesn't work well with Alk, (don't quite often test Ca since tank tolerance and inaccuracy of Hanna egg), as you said, lighting, GFO or other tank condition change such as coral stress from chemical warfare can easily change alk consumption, and yes 1dKH (18ppm) is about the limit they and I am comfortable with, I try to keep it between 7-8 dKH - this is hard to maintain without at least weekly attention sometimes daily, lazy and traveling a lot, that's hard for me, I can be more committed to monthly routines.

Assuming Alk/Ca consumption goes in balance (no reason to doubt that in my tank), the only problem trying to derive Alk from Ca reading is accuracy, I'm ok with 5ppm (1/4 dKH) or maximum 10ppm (1/2 dKH) on alk, so the question is can Pinpoint Ca reliably read Ca within 5-10ppm alk equivalent, or 2-4ppm Ca. If not then I'll have to forget about this tempting automation possibility.

Appreciate very much if you and fellow reefers can shed some light on their experience with Pinpoint or any other Ca monitoring, or even better direct Alk monitoring solution, then I'll figure out a way to make it work with controllers like ProfiLux.

 

[zzz111]

I agree that it's difficult to track alkalinity using the calcium numbers, due to accuracy limitations. I don't think that the calcium probe will work as a monitor, either. There's a review of it here:

http://reefkeeping.com/issues/2005-04/rhf/index.htm

It's possible to automate alkalinity testing by using an auto-titrator setup, but there's no commercial product available to do that. It'd likely be rather expensive, in any case.

Thanks Jonathan. Quick jump to the conclusion of the link review article, if the reading drifts in days, than not practical to expect 2-4ppm accuracy for acceptable alk tracking within 5-10ppm range. Thanks for saving me the money on another Pinpoint.

Just wondering how come the reefers are so less lazy as I am, to tolerant no solution to alk monitoring and automation. It's about the most active and most critical parameter in a "stable" reef tank, ph 7.8 to 8.5 fine I don't care, salinity happy enough with fixed dosing of fresh and salt water, P and N gone and when/if they do come by they'll knock on tank glass, organics we can't test and seem fine to live with - so it's alk, only alk. I've once spent the time to test alk at set times of day every day for a week to try establish some baseline, while it's kind of easy to predict time of day pattern, week over week consumption is hard to establish - living thing change all the time, like we catch a cold we eat less. Wish we can find a closed loop control system for alk, for hobby use of course, not yet ready to build a chemistry production line at home.

 

[bertoni]

Well, the issue mostly is cost. Someone built an auto-titrator and posted about it here, but it wouldn't be cheap to buy.

 

[zzz111]

Well, the issue mostly is cost. Someone built an auto-titrator and posted about it here, but it wouldn't be cheap to buy.

Hi Jon, do you remember how to find that post? Would be interested to have a look. To me, it's cost, space requirement, and ease of integration into the typical 0-10V analog input found on tank controllers, should be easy to find a suitable amp if the voltage is small. But if the output is a color change, then it'd be hard for me to mess with, also if it's a titrator, how to deal with waste water and rinse the vial automatically? Sorry a 1000ul pipette is the highest tech I've ever experienced in chemistry.

If all else ok, cost wise I value it to be well worth a high-end skimmer or a best in class LED lighting fixture - I'd be much happier living without one of those than this alk automation solution, but I sure can't sell my shelter since tank can't sleep in parks anyway.

 

[bertoni]

http://www.reefcentral.com/forums/showthread.php?t=1073780&highlight=alkalinity+automation

I think that's the only one.

 

[zzz111]

http://www.reefcentral.com/forums/showthread.php?t=1073780&highlight=alkalinity+automation

I think that's the only one.

This looks so coooooool!

 

[tmz]

Maybe that in addition to cost and technical complexity, the demand is low, since alk testing is inexpensive and easy. Calculating use isn't very hard and then automated dosing of a presset amount of calcium hydroxide or two part works quite well alongwith priodictesting and a rare tweakto maintain realtively consistent levels.

Good luck with you rproject though.

 

[scolley]

Good luck with you rproject though.

+1

And please post results here if you figure out a reasonably inexpensive DIY way to crack this nut. I'm subscribed here.

Thanks.

 

[zzz111]

+1

And please post results here if you figure out a reasonably inexpensive DIY way to crack this nut. I'm subscribed here.

Thanks.

From your post I see the same needs, I hope more of us would help people justify making it a product or at least a batch DIY. My hands are not up to the job so I'm trying to contact the genius who posted that DIY thread. The original post looks very, very promising to me, not sure why it stopped there at late 2008.

 

[zzz111]

Maybe that in addition to cost and technical complexity, the demand is low, since alk testing is inexpensive and easy. Calculating use isn't very hard and then automated dosing of a presset amount of calcium hydroxide or two part works quite well alongwith priodictesting and a rare tweakto maintain realtively consistent levels.

Good luck with you rproject though.

Hi Tom, your tank and your posts here helped me a lot, thanks very much. Sorry I'm the kind of forum user they call "scuba diver" here (meaning submerged never show up), I google "reefcentral and whatever I need", whenever I need to. This is about the first time I have to post to raise a question, usually I found my answer just searching and browsing, but I do owe you and a lot of the reefers here a lot of big thanks.

Yes it's easy to measure alk especially with the Hanna egg, and easy to set dosing pumps if and when the alk uptake is stable (or closely monitored), and if the tank is not hyper sensitive to alk swing, I mean within 0.5 dKH intra day or so. But in my case, first the tank for whatever reason (I suspect carbon dosing) is super sensitive to alk especially upswing, a bit over 8 dKH burns tips. Second, I spend most of the time traveling so automation is the key to success. And the level of automation determines the level of success.

If I can commit to a weekly or better twice weekly alk test, my tank might perform better. But the bloody reality is the tank has been experiencing alk swing cycles like this when I'm out for weeks from time to time: something like light tube failure or chemical warfare or else drive alk consumption down -> fixed dosing driving alk up -> tank too sensitive to alk up makes uptake even less -> most corals did make it but in a hibernation mode -> algae and others seize the opportunity and begin to grow -> alk over time consumed by unwanted bio, and maybe corals slowly adapt to the higher level, anyway untended in couple months or so corals do begin to grow again and surprisingly out compete algae, only to get ready for another alk swing. Sometimes coral grow too fast and I'm not available to adjust the dosing up, unfortunately my normal alk is at the lower side since the tank mates can't seem to tolerate higher, so there's hardly any room for downswing, they also go into "hibernation mode" to cause another alk upswing.

I know it's tough for my corals, my tank at any time when I'm home usually looks 1/3 good, 1/3 ok and 1/3 struggling a recovery, and I believe if I get alk rock solid through a closed loop control system, they should be much happier.

My laziness and frequent travel schedule might not be typical, but it seems hyper sensitivity to alk is not limited to my tank, at least many zeo tanks demonstrate that too. I suspect rock solid alk might help more tanks if implemented, even those well taken care of say with daily or twice weekly testing and adjustment, if we make it twice daily or more frequent. My alk swing cycles which can span months are probably the extreme case, but can we have smaller cycles like these in better attended tanks?

 

[tmz]

Thanks for your compliments.
I had no intention of discouraging the effort. Just responding to your question as to why no one had developed it. As you saw from the link last known effort peetered out a few years ago. I certainly don't have the skills or energy to take this kind of a project on.
I'm not sure a workable model is achievable at anything approaching reasonable cost with today's technology. The research and development alone seem as though they would be formidable. I'd fret about glitches in the solenoids, dosers,monitors, etc. too. I bet manufacturer's and developers would see leds, reactors.miracle fish cures etc as potentially more profitable efforts.
I understand the value of automation particularly for busy folks . Fortunately it's not as big an issue for me as a retiree. I'd like to see something like this functioning and do wish you good luck with it.
Bouncy alk frequently seems to to be in the mix when coral issues and crashes occur, particularly with sps. I am not ,however, certain it's a a cause for burnt tips or stn even in so called unls systems but suspect it may have something to do with it.

 

[zzz111]

Thanks for your compliments.
I had no intention of discouraging the effort. Just responding to your question as to why no one had developed it. As you saw from the link last known effort peetered out a few years ago. I certainly don't have the skills or energy to take this kind of a project on.
I'm not sure a workable model is achievable at anything approaching reasonable cost with today's technology. The research and development alone seem as though they would be formidable. I'd fret about glitches in the solenoids, dosers,monitors, etc. too. I bet manufacturer's and developers would see leds, reactors.miracle fish cures etc as potentially more profitable efforts.
I understand the value of automation particularly for busy folks . Fortunately it's not as big an issue for me as a retiree. I'd like to see something like this functioning and do wish you good luck with it.
Bouncy alk frequently seems to to be in the mix when coral issues and crashes occur, particularly with sps. I am not ,however, certain it's a a cause for burnt tips or stn even in so called unls systems but suspect it may have something to do with it.

Hi Tom, thanks a lot. I happen to also be in other hobbies of "small mass" too, like underwater photography, painful thing when you look at the available supply, but lucky enough already to have them around though. It's about how to make things easier and foolproof, to attract and retain more people to expand their customer base. Things like canister filter for freshwater and berlin for salt.

I don't even think my tank is a ULNS although I don't know the exact definition of it, I seldom test P and never test N, without P and N numbers it can't be a ULNS I guess whatever the definition is. I use my glass for indication, if I don't see traces of green brownish diatom powders on the glass in a week the water is too lean, or if they appear in 3 days it's too rich for me. That way my SPS are not thin or pale at all, their skin actually look a little bit thicker than those I see in nature, I need them to have that reserve to negotiate the tough conditions in my tank. But still they are overly sensitive to alk. When they were fat and brownish before carbon dosing, they didn't mind I raise ph from 7.8 to 8.4 by pouring limewater to sump.

I really wish to know why my tank mates get so sensitive to alk upswings, but really don't know, other than carbon dosing and lower nutrient. They weren't before I employed carbon dosing, but it's been verified many times now, by the repeatability of correspondence between slightly above 8 dKH alk and burnt tips. Yes the upswing of alk in fixed dosing system itself is a result of something else not going well, and my repeated observation shows it's a course of worse too, a positive feedback loop or a snowball effect. If one can stop the chain reaction earlier, the original event can probably pass without much noticeable trouble.

I'm glad they do survive though, through several such cycles, didn't know they're that hardy, most of the burnt tips get to hibernate for weeks and then recover, only very few tips failed to make it and became a scar on the colony. That's just in one cycle, over time now maybe half of my SPS have scared branches. If I can get my alk automated, the first thing after things stabilize I'd try to inch it up very very slowly see if they can adapt to a more moderate alk level, to leave some margin for downswing.

Glad I do have the choice between a brownish hardy tank or a colorful fragile tank with scars on SPS colonies here and there. Frankly I'm thankful enough to have this scared colorful tank given my availability of care, I'm actually amazed that they do survive the situations and even find their way back all on their own, well mostly. But if a solid alk level can stop these cycles and help prevent those scars from happening, that's basically telling the world ANYONE can keep a successful reef tank. Hope that comes true.

 

[tmz]

I've been dosing vodka and vinegar for 4 years and have colorful sps and other corals and hardy tanks, not brown ones and not amenic ones. PO4 is .02ppm to .04 ppm consistently with NO3 ,0.2ppm. Alk is kept in the 8.6 to 9.3 range, claim 460ppm and magnesium 1400 with sg of 1.026. UlNS ( ultra low nutrient system) is a meaningless term .
"Ultra" usually works for marketing and raises the price point though.In the hobby vernacular ulns iis usually associated with a total stripping of PO4 and NO3 to get as close to 0 as possible subsequently involving the use of supplements to put back some of what was taken out.

For further carbon dosing discussion , thjis thread may be of interest:

http://www.reefcentral.com/forums/showthread.php?t=2134105&highlight=organic+carbon+dosing

 

[zzz111]

I've been dosing vodka and vinegar for 4 years and have colorful sps and other corals and hardy tanks, not brown ones and not amenic ones. PO4 is .02ppm to .04 ppm consistently with NO3 ,0.2ppm. Alk is kept in the 8.6 to 9.3 range, claim 460ppm and magnesium 1400 with sg of 1.026. UlNS ( ultra low nutrient system) is a meaningless term .
"Ultra" usually works for marketing and raises the price point though.In the hobby vernacular ulns iis usually associated with a total stripping of PO4 and NO3 to get as close to 0 as possible subsequently involving the use of supplements to put back some of what was taken out.

For further carbon dosing discussion , thjis thread may be of interest:

http://www.reefcentral.com/forums/showthread.php?t=2134105&highlight=organic+carbon+dosing

Thanks Tom. That's a wonderful thread, I've read it before. Your research plus detailed personal experience made it the most useful carbon dosing reference among those I came across.

Carbon dosing has come along over the years from almost a hype (I thought they dosed in their month when first heard of it) to a verified working solution at least to many of its users. Still I don't know if we can say we understand it, other than we know it surely helps driving N and P down, more effective than most if not all other hobby available tools.

Aside from hyper sensitivity to alk upswing in my case and some other zeo tanks, which might or might not be related to carbon dosing, the super clear water is maybe a more commonly observed possible side effect of carbon dosing, as also mentioned in your linked thread. Although there can be a lot of reasonable explanations to it ("after fact wise man's theory" as we call such explanations here), the look of that "shiny" water is just unnatural to me, although totally pleasing. I have a plant tank sitting right next to the reef cube, before carbon dosing the plant tank water was clearer than the reef tank, kind of reasonable as coarse grain mud ball substrate with virtually no flow vs fine sands with 4 tunze pumps with no mechanical filtering, but ever since carbon dosing the reef tank looks noticeably clearer than the plant tank, even with all those fine particles still flying randomly all over the water column. I too once had a half-expected overdose which clouded water a little bit for less than a day, after it clears up, the tank's water really looked like shining light from itself, hard to describe with words. I don't see water like this anywhere in the nature, not even in 40m vis tropical sea in its best.

There is a lot I don't understand about carbon dosing beyond it's a powerful N/P export tool, looking forward to more insights from you and other fellow reefers.

Meanwhile I still have an alk sensitive tank to tender, was so encouraged by that DIY alk titration thread, and a bit disappointed that it just seem evaporated, hope the original poster will pop up somehow.

Thanks again and Happy Holidays!