How do I raise alkalinity?

[mharmon]

It's only in the last two months I've started paying much attention to alkalinity, PH, and calcium levels in an effort to slowly migrate to a reef system from fish only. From what I understand, high calcium tends to suppress alkalinity and I know I'll need both. Well, about 8 weeks ago my calcium tested over 900! I knew I had a problem seeing as the normal recommended maximum is something around half of that. I started doing 20% water changes every two days and after I'd done 5 changes, my calcium was down to the mid 500's. I've done a few more 20% water changes since then and my calcium is now down around 480.

To get to the point, I have had a hard time increasing my alkalinity to a consistent level over 2.0. I've dosed for about 2-3 weeks with baking soda and Kent Pro Bufffer dKH alternatively in the maximum recommended doses with little effect other than my PH is now between 8.0 and 8.2 up from 7.8.

As far as tank inhabitants, I have 1 damsel, around 10 astrea snails, one growing mushroom (~ 2"), 4 small hermits, and occasionally see my horseshoe crab. My substrate is reef grade aragonite about 1.75". Tank size is 10 gallons.

What can I do to raise alkalinity in a more permanent and stable manner? Do I need to lower calcium further? If so, is there a better way than water changes or livestock additions? Is nutrient export an issue?

Any ideas, advice, comments, etc. would be humbly welcomed!

[akm]

What type of salt are you using?

[mharmon]

Good question. Instant Ocean, I try to keep it around 1.026 SG

[kkutac001]

I am in a similar boat with mharmon. Ca was up over 600ppm; dKH is steady at 8.4 (3.0 meq/L). I use IO salt, too. However, I think I know exactly how my water got this way. (I'm pretty new to s/w aquars) I was topping off with pure RO water, while at the same time using SeaChem Number 28 cubes. I wondered why they disolved so fast. I think I was really eating up my buffer, allowing a whole bunch of Ca to dissolve into my water. I was hoping there was a better solution than a 100% water change over 14 days.
Is there no other way to "soak up" the Ca? I've seen phosphate media, active carbon for organics, ammonia media.... Anyone heard of a "Calcium sponge" or whatnot?

[Richard]

Those sealab blocks are a decent product for smaller tanks if you don't mind using calcium chloride. However, most people don't use them correctly. The manufacturer recommends shoving them down in the sand or otherwise protecting then from any current flow. Otherwise they dissolve too quickly.

[matt]

I kind of doubt you really had Ca levels of 900, really sounds like a test kit problem, unless your ph was so low that almost nothing would survive. Anyhow, plain baking soda will raise your alkalinity as well as anything, but won't affect your ph too much. Probably the best way to keep Ca and Alk relatively stable in such a small tank is to drip kalk periodically. I assume in the 10 gallon you don't have a sump, so you can use one of the Kent dosing "drippers" right into your tank; best to do it at night or early in the morning before the lights come on. Make sure you drip into a high flow area and don't do too much; maybe a cup or two at a time, dripped as slowly as the dripper will let you.

A better long term solution would be to set up a small sump; another 10 gallon would work fine. Then you can use a glass jug, a 2 holed stopper, some pyrex pipe, and some tubing to set up an auto top-off. As water evaporates from your sump, you can use the auto top off to replace your evaporated water with kalkwasser. I did this for a few years on my old 10 gallon and it worked great. BTW, I would not use IO salt, especially in a nano reef. Water changes in such a small tank can really upset things, and IO is terrible with regards to ph shifts when it's just mixed up. The marine environment salt is much better IMO, and I also like the bio-assay salt, but others had some problems with it. Whatever you use, make sure to aerate the newly mixed up salt for at least a day with an airstone, or a powerhead with an airpump attached to the little venturi nipple that most powerheads have. That works pretty well, and you can usually get IO up to 8.2-8.3 before you add it to your tank.

[gjuarez]

Gary (GaryP) has a nice formula where he uses baking soda and washing soda. You might want to PM for that. Many people have had great success with it.

[GaryP]

The key to raising alkalinity is not what you use, but how you are applying the product. If you see a white cloud when you add it, you are precipitating calcium carbonate (aragonite) and you basically wasted the product. This is even more so when your calcium levels are high. You may just be bringing your calcium levels down by making sand. I prefer dripping buffer diluted with RO water slowly into a turbulent area of my sump where it mixes quickly. Remember that there are other demands on alkalinity besides coral growth. Bacterial activity in the tank produces acids that will neutralize the buffer.

Also, test your magnesium levels. Magnesium plays a role in the calcium/alkalinity balance by acting as a precipitation inhibitor. Your magnesium level should be about 1400-1500 ppm. This is often a problem in tanks where it is difficult to maintain a balance. I would try to get your calcium down to the 425-450 range.

You didn't give what units you are using for alkalinity. I assume you are using meq. If you are, then you want to shoot for an alkalinity concentration of around 3-3.25 meq/l. If you are using Dkh units your want to be around 8.5-9.0. Some critters are sensitive to rapid changes in alkalinity so any change you make should be done slowly. That's another advantage to the drip method.

After you get your alkalinity and calcium where you need it, I would suggest do a lot of daily testing for a while to determine what your daily demand for both are. Adjust your dosing of additives accordingly so that you don't have wild swings in concentration during the week. As you add corals, and other consumers of alkalinity and calcium these daily demands will increase so periodic testing is necessary to get a handle on these changes.

[mharmon]

I kind of doubt you really had Ca levels of 900, really sounds like a test kit problem, unless your ph was so low that almost nothing would survive. Anyhow, plain baking soda will raise your alkalinity as well as anything, but won't affect your ph too much. Probably the best way to keep Ca and Alk relatively stable in such a small tank is to drip kalk periodically. I assume in the 10 gallon you don't have a sump, so you can use one of the Kent dosing "drippers" right into your tank; best to do it at night or early in the morning before the lights come on. Make sure you drip into a high flow area and don't do too much; maybe a cup or two at a time, dripped as slowly as the dripper will let you.

A better long term solution would be to set up a small sump; another 10 gallon would work fine. Then you can use a glass jug, a 2 holed stopper, some pyrex pipe, and some tubing to set up an auto top-off. As water evaporates from your sump, you can use the auto top off to replace your evaporated water with kalkwasser. I did this for a few years on my old 10 gallon and it worked great. BTW, I would not use IO salt, especially in a nano reef. Water changes in such a small tank can really upset things, and IO is terrible with regards to ph shifts when it's just mixed up. The marine environment salt is much better IMO, and I also like the bio-assay salt, but others had some problems with it. Whatever you use, make sure to aerate the newly mixed up salt for at least a day with an airstone, or a powerhead with an airpump attached to the little venturi nipple that most powerheads have. That works pretty well, and you can usually get IO up to 8.2-8.3 before you add it to your tank.

Yes, I too suspected that I had a bogus number. That is why I took my water to Fin-Addict and had them test it. Their reading was spot-on with mine, using a different test kit. Perhaps after a certain level, Ca does not test in a linear fashion. But it did seem to drop in a linear fashion. I suspect my salt mix and the No. 28 cubes I'd been putting in, appearently incorrectly, over the last year plus.

With my last water change, I used the last of my IO mix and the next change will be with Crystal Sea Marinemix. BTW, I mix, aerate, and filter my mixed water for at least 24 hours before I use it. I use store-bought RO water for mixing.

No, I don't have a proper sump, but I do have a Bak-Pak 2 with the supplied filter media replaced with chaetomorpha. I also have a Penguin 170 HOB running carbon replaced every two weeks. I'll probably drip through one of those two means. Will kalkwasser raise my alkalinity in an even fashion with my calcium?

Eventually, I suspect I will upgrade this tank to around 55 gallons and this 10 gallon will turn into a sump. My girlfriend is concerned that the kitchen bar can't take the weight, however... :innocent It has 47 gallons on it now and I don't *think* it's collapsing.

Thanks for the great info!

[mharmon]

The key to raising alkalinity is not what you use, but how you are applying the product. If you see a white cloud when you add it, you are precipitating calcium carbonate (aragonite) and you basically wasted the product. This is even more so when your calcium levels are high. You may just be bringing your calcium levels down by making sand. I prefer dripping buffer diluted with RO water slowly into a turbulent area of my sump where it mixes quickly. Remember that there are other demands on alkalinity besides coral growth. Bacterial activity in the tank produces acids that will neutralize the buffer.

Also, test your magnesium levels. Magnesium plays a role in the calcium/alkalinity balance by acting as a precipitation inhibitor. Your magnesium level should be about 1400-1500 ppm. This is often a problem in tanks where it is difficult to maintain a balance. I would try to get your calcium down to the 425-450 range.

You didn't give what units you are using for alkalinity. I assume you are using meq. If you are, then you want to shoot for an alkalinity concentration of around 3-3.25 meq/l. If you are using Dkh units your want to be around 8.5-9.0. Some critters are sensitive to rapid changes in alkalinity so any change you make should be done slowly. That's another advantage to the drip method.

After you get your alkalinity and calcium where you need it, I would suggest do a lot of daily testing for a while to determine what your daily demand for both are. Adjust your dosing of additives accordingly so that you don't have wild swings in concentration during the week. As you add corals, and other consumers of alkalinity and calcium these daily demands will increase so periodic testing is necessary to get a handle on these changes.

Thanks for the great info! Yes I'm using meq/l units on the alk. I'm going to invest in a dripper and Mg kit first chance I get. However, I haven't seen the drippers for sale. Is it because I haven't been looking hard enough or asking enough people or do I need to get them from a medical supply store instead of the LFS?

[Belowh20]

You can make a cost effective simple dripper with a gallon jug and some airline tubing. IV tubing works well too.

If you go to a medical supply store they should sell IV tubing with an adjustable dripper, this usually works better than airline tubing. All you need to do is cut a small hole to fit the tubing about 1-1 1/2" inches from the bottom of the jug and silicone around the hole to make it water tight. Then you can adjust your drip rate to slowly top-off your evaporated water, as well as keep your levels stable.

Another option in such a small tank is B-Ionic or a similar 2 part mix. I have found this to be the easiest way to keep levels stable in my 10g reef.

[kkutac001]

Richard, thanks for the SeaLab block advice. I actually do not want calcium chloride. From the other msgs, it seems there is no "calcium sponge" (or whatnot). A follow-up I'd like to ask is: Lots of people say you can add baking soda (or some other buffer/alk product) to increase alk, but with Ca so high (500 or 600 or whatever), is there not an excellent chance of creating a catastrophic precipation event?

[matt]

Yep, just add it slowly. Gary's dripping idea is good.

[mharmon]

My calcium is down to 300, alkalinity is up to 2.75 meq/L and ph is 8.2. If I start a slow kalkwasser drip, will that increase my alkalinity as well as calcium?

[Richard]

Not really. Kalkwasser helps maintain alkalinity but doesn't really raise it.

Your going to have a tough time getting your calcium up to the 400 range off of just kalkwasser. I would use calcium chloride to raise it back up to where you want it and then start using kalkwasser to maintain that level.

Isn't this chemistry fun :roll

[Richard]

This calculator might be useful for you...

http://www.kademani.com/reefchem.htm

[mharmon]

Not really. Kalkwasser helps maintain alkalinity but doesn't really raise it.

Your going to have a tough time getting your calcium up to the 400 range off of just kalkwasser. I would use calcium chloride to raise it back up to where you want it and then start using kalkwasser to maintain that level.

Isn't this chemistry fun :roll

Thanks for the info. Can I drip a solution of baking soda and calcium chloride?

[Richard]

No you want to keep calcium and carbonates seperate or you'll just make some sand (calcium carbonate).

[matt]

Actually, depending on your load, kalkwasser can raise both calcium and alkalinity. It's just that normally, we tend to overload our tanks and kalk can't keep up. What's in your tank again? Is it heavily loaded with corals, or is there a light calcium load? Going from 900 (supposedly) to 300 is pretty drastic. I bet you were nowhere near 900; calcium test kits are not accurate in that range anyways, I think. It doesn't matter. If you have your salt worked out, I'd do a couple of big water changes with Marine environment salt. (check the the Ca, alk, and ph of the new stuff before you put it in) Since you have a 10 if I remember, it won't be much work. As long as the temp, ph, Ca and alk are all good with the new stuff, you won't stress your tank too much. At that point, you should be in pretty good shape to drip kalk. Constantly messing with Ca and Alk levels in such a small system is pretty frustrating and terrible for the inhabitants.

[mharmon]

Actually, depending on your load, kalkwasser can raise both calcium and alkalinity. It's just that normally, we tend to overload our tanks and kalk can't keep up. What's in your tank again? Is it heavily loaded with corals, or is there a light calcium load? Going from 900 (supposedly) to 300 is pretty drastic. I bet you were nowhere near 900; calcium test kits are not accurate in that range anyways, I think. It doesn't matter. If you have your salt worked out, I'd do a couple of big water changes with Marine environment salt. (check the the Ca, alk, and ph of the new stuff before you put it in) Since you have a 10 if I remember, it won't be much work. As long as the temp, ph, Ca and alk are all good with the new stuff, you won't stress your tank too much. At that point, you should be in pretty good shape to drip kalk. Constantly messing with Ca and Alk levels in such a small system is pretty frustrating and terrible for the inhabitants.

I expect I have a rather light calcium load: 1 ~2" Mushroom (growing rather well), 1 small damsel, 10 astrea snails, and 4 small hermits. Oh, and about a quart of chaeto in the Bak-Pak 2 hanging on the back.

I plan to perform another 20% water change soon. I'll measure the levels in the mix before I pour it in and we'll see how that levels things out. I have one question though: How long will prepared mix last before use? I've mixed the mix and aerated it for over 24 hours and stored it in two 1-gallon jugs for easy measurement and handling. How long do I have before I should use it?

[matt]

It'll last indefinitely. The Marine Environment stuff that I used recommended mixing the whole bag at once, something like 40-50 gallons. You can keep that in a clean trash can, covered for several months with no ill effects at all. Once it's mixed and aerated, and adjusted for ph, Ca, Alk, you don't have to keep it moving.

[Richard]

Oops...I didn't spot that this was a 10 gallon tank. Given that it's such a small tank, I wouldn't dose ANYTHING. A 10 gallon is easy to maintain with just water changes. Whatever salt floats your boat will work.

[mharmon]

It'll last indefinitely. The Marine Environment stuff that I used recommended mixing the whole bag at once, something like 40-50 gallons. You can keep that in a clean trash can, covered for several months with no ill effects at all. Once it's mixed and aerated, and adjusted for ph, Ca, Alk, you don't have to keep it moving.

The reason I asked is that I had a gallon left over from the last water change and it sat in the bucket I'd mixed it in for a week. When I reached into the water to test SG, there was this very clear, nearly invisible thick layer of slime on top. It look a lot of rinsing to remove the slime from the bucket. I don't know what that was, but I suspect it was biological. :sick