Calcium reactor tuning help

[Aaron]

Just setup a calcium reactor on my system yesterday.

I am running a milwaukee pH controller to switch on/off the CO2.

Thought I had everything figured out, but I really need some input from someone that has experience with these devices.

When the pH in the chamber rises to 6.7, I have the controller set to turn on the CO2.

The CO2 is set with a bubble rate of about 60 bubbles per minute.

How long should it take for the pH in the chamber to drop to 6.5?

I am resisting the urge to tinker with things, don't want to screw something up, but...

It seems like it takes a long time for the change to register (pH to drop)......

I'm kind of freaking out, but trying to take a valium and relax instead of making the assumption that this thing isn't working correctly.

 

Help??

[Coral Hind]

It does take time for the pH to drop. The flow rate of water through the system is important. How many drops per minute are you running? Make changes slowly and wait at least 24hours between changes.

[Aaron]

Right now I have it running about 120 drops per minute into the skimmer output.

I am so glad to hear that this is normal :-)

Will definitely be glad when it is tuned in and I can leave it alone.

[Der ABT]

Ha was just typing the same it does take a while an i ts best to set a drip rate and then if you need more alk then just drop the ph a little but i f you go too low u can turn the media to sludge

[Aaron]

Thanks! I did notice yesterday when I first got it running that a lower pH definitely boosted the alkalinity and allowed me to drip a smaller amount for the same effect.

 

However.... I also noticed that running it that slow seemed to lead to the effluent tube getting clogged over a period of a few hours. Definitely don't want a meltdown on my hands, so I raised the pH a little and increased the flow.

 

I can see that this may take me a while to get perfectly tuned to the system, but I was sooooo tired of doing the two part dosing every day. I was losing close to 2 dkh per day and sometimes would forget to dose, which would cause a huge swing in the parameters over a 48 hour time period.

 

Right now I have the large ARM media and about half a jug of NeoMag in there, and I _think_ I have settled on a pH of 6.5

 

So far there doesn't seem to be a big downward impact on my pH, glad to see that.

[Der ABT]

I run 6.6 and drip about 1.5 -2 drips a second on my sys of about 150 g I noticed sludge in arm around 6.4-6.5 so I'm just over it and do have to clean the lines every few months but not daily I using a maxi jet 900 for a feed I think may be a 1200

[Aaron]

Fortunately I decided to put valves in my plumbing when I was setting things up. Was originally going to feed it with a maxijet 1200, but then I started thinking about what would happen in a power outage, and it got me scared. I was worried about the possibility of the contents back siphoning into my sump. So, instead of the maxijet, I shut down my return pump, closed the valve, cut into the pipe and plumbed in a T.

From the T, I converted from PVC to 1/4" id tubing, put in a valve with quick connects, and then ran the tubing down to the input of the reactor.

I hope this was a smart idea - it seemed like a good idea at the time (then again, so many things do in life).

[Der ABT]

Very good idea I just haven't gotten around to it but it may be good to have the return cut back a little above where the t is to ensure good pressure to the reactor sounds like your doing good though now just sit back and watch the growth

[Aaron]

Good idea. I hadn't thought of that.

[Aaron]

Ok, so here's where I'm at with things now.

I left it alone last night, and it did in fact do exactly what it is supposed to do.

The pH dropped appropriately, and the system continued to drip into the high flow area by my skimmer output.

There is really little to no change in my tank pH.

 

I ran a series of tests when I got home from work last night (this is about an hour after my main lights come on), and this is what I got:

 

pH - 8.0

Alk - ~10 dkh

Cal - ~420 ppm

Mag - ~1340

 

Then, this morning before I got in the car to go to work, I checked everything out, the equipment looked to be functioning properly, no leaks, no blockage, appropriate pH. Ran another series of tests to see where things were after about 7 hours of sleep time (the lights shut down at 3 AM, and I did the tests at about 7:30):

 

pH - 7.9 (I am ok with that, don't think it is a problem)

Alk - ~12.2 dkh

Cal - ~440 ppm

Mag - ~1350

 

I assume I am approaching saturation at this point, probably need to dial it back a little?

Maybe raising the pH in the reaction chamber is a good idea?

Just wondering what people's advice is here.

 

Thanks to everyone that has given their input!

[Der ABT]

i usually run the test at the same time of day ( not sure it really matters but its also the only time i have after work/baby duties etc)

sounds like you should just turn up the ph a little, i would only do it by tenths, aka if you have 6.5 go to 6.6 in the chamber and leave the drip rate alone. that is the best way to tune it imo. (granted i have less than a year with a reactor ive gotten mine pretty stable) then test it again the next day, if still increasing do another tenth, if only slight increased wait till the next day to test, and eventually you could space your testing out.

 

Ph drop is normal, i see my ph go from 8.3 to 8 at night especially when my kalk reactor is running a little low. my kalk reactor just uses my top off, if i used a dedicated pump to it i wouldnt be suprised if i could get things more stable but im ok with it the way it is

 

again the key is to go slowly and the good thing of turning the ph up in the reactor is that when things grow you know all youll have to do is lower the ph a little till its gets so low that you have to adjust the drip rate.

[Origami]

Ok, so here's where I'm at with things now.

I left it alone last night, and it did in fact do exactly what it is supposed to do.

The pH dropped appropriately, and the system continued to drip into the high flow area by my skimmer output.

There is really little to no change in my tank pH.

 

I ran a series of tests when I got home from work last night (this is about an hour after my main lights come on), and this is what I got:

 

pH - 8.0

Alk - ~10 dkh

Cal - ~420 ppm

Mag - ~1340

 

Then, this morning before I got in the car to go to work, I checked everything out, the equipment looked to be functioning properly, no leaks, no blockage, appropriate pH. Ran another series of tests to see where things were after about 7 hours of sleep time (the lights shut down at 3 AM, and I did the tests at about 7:30):

 

pH - 7.9 (I am ok with that, don't think it is a problem)

Alk - ~12.2 dkh

Cal - ~440 ppm

Mag - ~1350

 

I assume I am approaching saturation at this point, probably need to dial it back a little?

Maybe raising the pH in the reaction chamber is a good idea?

Just wondering what people's advice is here.

 

Thanks to everyone that has given their input!

 

You can either raise the pH in the reaction chamber to reduce the effluent concentration, or reduce the drip rate so that you're delivering less effluent to the tank. Either way will work. If you're able to successfully micro-adjust the drip rate (and keep it stable), then this will probably be easier to do. However, microvalves have a way of clogging rather quickly at slow drip rates so you may find this approach has challenges. It's less of a challenge if you're delivering effluent through something like a peristaltic pump.

[Coral Hind]

I don't remember seeing it mentioned but what unit are you using and what size is your reef tank?

[Aaron]

Yeah, I never did post any tank specs really. It isn't fancy by any means.

 

40 gallon acrylic, 20 gallon sump (rubbermaid ) - at least I plumbed everything with PVC.

Euroreef RS-100 skimmer (upgraded pump from KSP-3500 to KSP-5000)

Nextreef MR-1 (I run activated carbon, then a layer of filter floss, then a layer of GFO)

Medusa temperature controller (right now controlling 4 fans, set to come on @ 80.5)

JBJ auto topoff

Mag 5 return pump

For lighting I am running 2x39W T5 Super Actinic and 2x150W Radiums.

Calcium reactor - designed exactly like the Reef Octopus CR-140D (dual chamber). It isn't a Reef Octopus, but it doesn't have a brand name on it anywhere that I have found.

[Origami]

Aaron, do you really have the calcium and alkalinity consumption now that requires a calcium reactor?

[Aaron]

You know, that is a very good question, and I appreciate your insight.

The reason I say this is because I would have thought no.

But, as soon as I started using the GFO media, my alkalinity was dropping at an increasing rate every day.

I thought initially that it was because I was using too much media, so I made adjustments to compensate (i.e., less GFO, considerably less).

It made absolutely no difference. So, I have been losing on average around 2 dkh per day. I'm sure others have much more consumption than that, but the point being that it was requiring me to dose two part every day, and if I happened to forget, well then I go from 9 dkh to 5 dkh in a 48 hour period, and the swings were causing noticeable reactions in the tank, as well as a downward pH trend.

As far as livestock, I have about 7 SPS colonies most of which are pretty small (green slimer, orange monti, tyree pink lemonade, ORA red planet, pink pocillopora, ORA blue tort, purple bonzai), about 3 LPS (hammer (4 heads), frogspawn (3 heads), acan lord (about 6 inches diameter)), star polyps (large colony), 2x kenya tree colonies, about 6 blue mushrooms... I know I must be missing something...

Does it sound to you like my reported consumption falls in line with the stocking of the tank?

[Origami]

Aaron, I have a few questions for you.

 

First, have you been seeing a commensurate drop in your calcium level along with the loss in alkalinity? For every milliequivalent (1 meq = 2.8 dKH) of alkalinity consumed, you should see a 20 ppm drop in calcium if calcium carbonate is being precipitated out.

 

Second, do you see a white precipitate on your GFO granules? If so, it's probably calcium carbonate precipitating out on the GFO and causing the alkalinity loss. You can also check by putting some GFO in vinegar and looking for the telltale bubbles of the CaCO3 dissolving. (I'm assuming that you're using the GFO to take care of issues with phosphate?)

 

Third, do you have a nitrate problem? What are your nitrate levels? In the first couple of steps of the nitrification cycle (ammonia to nitrite, then nitrite to nitrate), a unit of alkalinity is consumed. That unit is returned in the nitrate to nitrogen gas step. So, if you have a nitrate problem and are handling it through water changes or some other (export) mechanism, alkalinity can drop in disproportion to calcium consumption.

 

Rather than GFO and a calcium reactor, I would have thought that a kalk stirrer might have been a better first step, or even a two-part dosing system. Kalk will help keep your pH higher and will help bind up phosphates. Both are desirable, but kalk (calcium hydroxide), which is normally delivered to your tank through your topoff water, has low solubility, and this means that it can only go so far to keep up with calcium and alkalinity consumption. Normally, for less mature tanks, this is not a problem.

[Aaron]

Aaron, I have a few questions for you.

 

First, have you been seeing a commensurate drop in your calcium level along with the loss in alkalinity? For every milliequivalent (1 meq = 2.8 dKH) of alkalinity consumed, you should see a 20 ppm drop in calcium if calcium carbonate is being precipitated out.

 

Yes, I do see a matching drop in calcium

 

Second, do you see a white precipitate on your GFO granules? If so, it's probably calcium carbonate precipitating out on the GFO and causing the alkalinity loss. You can also check by putting some GFO in vinegar and looking for the telltale bubbles of the CaCO3 dissolving. (I'm assuming that you're using the GFO to take care of issues with phosphate?)

 

No, I do not see any white precipitate on the GFO media or around it.

 

Third, do you have a nitrate problem? What are your nitrate levels? In the first couple of steps of the nitrification cycle (ammonia to nitrite, then nitrite to nitrate), a unit of alkalinity is consumed. That unit is returned in the nitrate to nitrogen gas step. So, if you have a nitrate problem and are handling it through water changes or some other mechanism, alkalinity can drop in disproportion to calcium consumption.

 

I actually just replaced my RO membrane and pre-filters about two months ago. Tests for nitrate and phosphate always come back undetectable (though I have not spent huge money on a phosphate colorimeter. I have three fish - a mated pair of clowns and a chromis, feed them about every other day with Rod's food. I don't believe there is a nutrient problem, but I have been wrong before.

 

Rather than GFO and a calcium reactor, I would have thought that a kalk stirrer might have been a better first step, or even a two-part dosing system. Kalk will help keep your pH higher and will help bind up phosphates. Both are desirable, but kalk (calcium hydroxide), which is normally delivered to your tank through your topoff water, has low solubility, and this means that it can only go so far to keep up with calcium and alkalinity consumption. Normally, for less mature tanks, this is not a problem.

 

The reason why I didn't go the kalk route is because I have used it in the past and found it to require a lot of maintenance and attention (limited shelf-life, mixing it up, regular cleaning, etc). On top of that, if something gets hosed (a float switch, a pump, etc) you end up overdosing the tank and torching everything. I realize things can go wrong with any system, but from my perspective I would much rather set something up that can be filled with media, dialed in, and go. For my system, a 5lb CO2 cylinder and 8lb package of ARM should easily last for 12 months.

I don't necessarily disagree with your suggestion, but I went this route so that when I setup the 90 gallon that I have in the basement, I won't have to buy another reactor

[Origami]

It may be going to coral growth - that's entirely possible (but, it's a fair amount of growth). Especially if you had a phosphate problem before (phosphate can interfere with calcification, so if your GFO pulled phosphate from the water column, things could have begun to take off. If so, you should be seeing something whether its in your corals, coralline algae, or precipitation on parts of your system (heaters, pumps, etc.)

 

Try testing your GFO for calcium carbonate precipitate by putting it in some vinegar (just for grins) since the alkalinty decline coincided with the addition of GFO to your setup.

 

If you're seeing a 2 dKH drop in alkalinity in 24 hours due to calcification (that is, if the alkalinity is not going elsewhere), that translates to about 35 ppm calcium (or, considering the density of salt water, about 139 mg of calcium carbonate formation per gallon of salt water). Let's say that, with displacement, your actually ahve about 40 gallons of water in your system. In this case, the math says that you're getting about 5.5 grams of calcium carbonate formation every day, or about 5.7 grams of coral skeleton (if that's where it's going) if that skeleton has 3% magnesium by weight. That's every day. This would imply that you're laying down around an ounce of coral skeleton in 5 days, or about a pound every 3 months.

 

I found an interesting paper on coral skeletal densities here. If, from that, we use the conservative figure of 2.5 grams per cubic cm of coral skeleton, you should be seeing something like 180 cc's (~11 cubic inches) of growth every 3 months if all that alkalinity is going to coral growth and not being lost elsewhere.

[Aaron]

Wow

Yeah, I wish I was seeing that kind of growth, but I'm definitely not. So, it sounds like some of your other theories may be at work here.

I'll need to do the testing you mentioned to confirm.

You are always a wealth of information, and have helped me out many times in the past.

I'm still fairly new to the hobby (at least in a serious capacity), and I definitely want to provide the best possible environment for the animals.

Thanks for being such a great resource to the group!

[Origami]

BTW, there are ways other than chemical that calcium and alkalinity (and more) are exported. It's also lost in your skimmate. Here's a fun article from advanced aquarist magazine that ran earlier this year:

 

Elemental Analysis of Skimmate: What Does a Protein Skimmer Actually Remove from Aquarium Water?

[Origami]

I did a quick calculation upon re-reading the skimmate article that I linked above. It seems that in the author's second experiment, approximately 1% of the mass of the liquid skimmate from his skimmer was calcium carbonate. Now, keeping in mind that skimmate quality can be highly variable between our setups, if we use this figure as just a rule of thumb, then a skimmer that pulls 1 cup (237 ml) of skimmate per day, will pull about 2.5 mg of calcium carbonate per day from the tank. That's about half of the 5.5 mg that I calculated earlier and it halves how much could go to things like coral, coralline, and other calcifying organisms.

[Aaron]

I did a quick calculation upon re-reading the skimmate article that I linked above. It seems that in the author's second experiment, approximately 1% of the mass of the liquid skimmate from his skimmer was calcium carbonate. Now, keeping in mind that skimmate quality can be highly variable between our setups, if we use this figure as just a rule of thumb, then a skimmer that pulls 1 cup (237 ml) of skimmate per day, will pull about 2.5 mg of calcium carbonate per day from the tank. That's about half of the 5.5 mg that I calculated earlier and it halves how much could go to things like coral, coralline, and other calcifying organisms.

 

This might actually be a possibility then. The four animals that have shown the most significant growth have been the orange monti, green slimer, red planet, and long tentacle anemone. I know the anemone probably doesn't go into the equation at all here, but the thing is becoming a limiting factor in the tank due to its growth . That being said it is one of my most favorite additions - thank goodness I went with a DSB when I set up the tank. It has parked itself, and not moved since about 24 hours after I brought it home, and I have kept it (believe very happy) for about six months now. Plus when I got it I was completely inexperienced, and didn't realize it was totally bleached and on the verge of death. When it first started turning brown, I thought something was wrong with it...

 

The orange monti has probably grown an inch in diameter over the last three weeks, the red planet has encrusted over the base where I adhered it about 1/2" over the same period, and the green slimer is growing at a phenomenal rate, though not in the pattern I expected. Rather than growing _up_, it is growing horizontally and down, specifically into the most intensely lit area in the tank.

I'm actually sitting here admiring things tonight because I have come such a long, long way from the 8 gallon biocube that I started with (in this house) two years ago.

 

I have not setup the 90 because we are planning to buy a house this summer, and I want to build something into a wall with a proper "fish room" behind it.

 

Thanks again for sharing your wisdom Tom.

Edited December 9, 2010 by Aaron

[Origami]

...I'm actually sitting here admiring things tonight because I have come such a long, long way from the 8 gallon biocube that I started with (in this house) two years ago.

It's a nice feeling, isn't it?

[GaryL]

So, it sounds like some of your other theories may be at work here.

 

 

i wouldnt call it a theory, lol. Tom almost always seems to have it locked down.