Juggling KH CA and PH

[Bill_68]

I was wondering how important KH levels are in SPS tanks.

 

I recently added a bigger refugium to an aging tank. I have Lots of bubble algae. It was getting more red fuzzies and green slime algae issues and Low CA. I can't keep a astrea or turbo alive for over 3 months, tops. I took out some crushed coral sand.

 

I increased flow and started dosing CA. Sps growth is increasing. Algae is decreasing slowly. Coralline algae is slowly increasing. PH was high, but I suspect the general shift is from anaerobic to aerobic. I also. Set my temp from 80 to 78, and dropped my salinity to .oo24 from .oo27. I read that lower salinity would allow for better o2 levels.

 

This evening I took some readings.

 

Ammonia 0

Nitrites 0

Nitrates 0 - 5 ish hard to tell.

PH 8 or 8.2

CA 400

KH 6/107

 

Anyhow the KH seems off. Tests were API, which seem okay if you test a few times if results seem off.

 

Any thoughts? I really want to keep some more delicate sps species. I have acros growing with long tentacles (a green one, lt blue, birds nests (pink), two white w/ blue and green tips) some orange montiporas, and a greenish spotted sheeting thingy about the size of a small plate. I also have two corals that I forgot their names. They look like really thick acroporas. Very lumpy. Not milliporas. Sort of fuzzy looking. Lobular. One is pink, while the other is blue. They all seem very hardy. Any ideas what is whacked with my water chemistry?

 

Positive suggestions appreciated.

 

Bill

[seabass]

Test a batch of your freshly mixed saltwater to see if the levels are within normal ranges. If they aren't, switch salt mixes. I use the levels of the mix as the target for dosing (attempting to keep the levels stable versus elevating them). And yes, alkalinity is important.

 

Test your water's magnesium level. If magnesium is low, adding calcium will push alkalinity out of suspension.

 

With a fuge, you might not show high inorganic phosphate levels, but I would test those too (using a decent low range phosphate test kit). You want them to be around 0.03ppm.

[Mr. Fosi]

I agree with the bass on all points.

[doppelganger]

KH is very important to the health of coral. You're KH is off cuz ur dosing only calcium. If you only dose calcium and not alk, alk will continue to drop and rapidly as well. The change in KH is drastic while calcium depletion appears much slower. I feel like you'll probably need to read up on water chemistry more if you plan on keeping more challenging SPS. Especially for the "sheeting fuzzy lobular, blue white pink thingy's"

 

Take away: KH is VERY important. Read up on water chemistry: Calcium, Alkalinity, Magnesium and how they balance each other.

[Bill_68]

Okay, so Alk is merely an indicator of the ratio of the different Calcium forms in solution although not the proportion. By testing adjusting Magnesium levels, I can then test to see what Calcium levels are doing dispite their form. Magnesium just allows you to push the Ca levels up instead of it precipating out?

 

So ... as long as PH 8.2 or so, and Calcium is above 400 or so, life should be Okay... or are corals fussy about what form of Ca they use?

 

I do bring my water in to be tested at the local fish store, Nitrates, Nitrites, and Ammonia are zero.

 

Which brings me to to the question of why Calcium needs to be dosed at all. I mean shouldn't water put the stuff in solution all the time, or are the little pink sheeting fluffy thingies fixing Calcium faster than water can dissolve it? IE Dose Ca. Oh, and it you use quotes, copy and paste between them... paraphrasing is okay as long as it's accurate.

 

"Not milliporas. Sort of fuzzy looking. Lobular. One is pink, while the other is blue.", wrote Bill.

 

 

 

 

 

 

[doppelganger]

Just a joke...

 

Yes, water does put the elements back. Think about it this way, if you have absolutely nothing uptaking CA and KH to build their skeletons, then you would never need to dose. But that's not usually the case. As soon as you start adding SPS, and LPS that use those elements you'll need to replace them. You could get away with constantly doing water changes depending on how fast Calc and alk are being used, but in most cases especially in SPS dominate tanks, you won't be able to keep up a get those levels stable which is why people dose calc and alk.

 

Salt is $$$. Calcium and alk 2 part or other things are typically much cheaper. For those that have mature tanks or are lazy, then water changes are done less often meaning you can count on that to balance out your calc/alk.

[Bill_68]

Yep, I was just wondering how fast salt water could dissolve crushed coral and such. I would think it would tear it apart fairly quickly, but I guess you have quite a few other factors. Anyhow, I just got done with a 20 gallon water change. Um... er.. 15%. Hopefully that will cut the organics back and add some ions back into the mix.

 

I do like your little API chart. Kinda reminds me of the PH chart. Anyhow, I guess I will do some more testing tonight and see what happens to KH.

 

Enjoy the Day,

 

Bill

[seabass]

Okay, so Alk is merely an indicator of the ratio of the different Calcium forms in solution although not the proportion.

We mostly consider alkalinity (carbonate hardness) to be the concentration of carbonate and bicarbonate (which are more important components of alkalinity than calcium). We dose these separate from calcium to avoid precipitation.

 

By testing adjusting Magnesium levels, I can then test to see what Calcium levels are doing dispite their form.

The magnesium level doesn't really give you any information about calcium or carbonates.

 

Magnesium just allows you to push the Ca levels up instead of it precipating out?

Yeah, basically. Natural sea water (NSW) levels of magnesium make NSW levels of calcium and alkalinity possible. The two could not both remain in suspension without magnesium. However, magnesium is also aids in calcification of coral structures.

 

So ... as long as PH 8.2 or so, and Calcium is above 400 or so, life should be Okay... or are corals fussy about what form of Ca they use?

I normally don't worry too much about pH. However, dosing can affect pH, so it's not a bad idea to check it when dosing (as certain additives can affect pH more than others). However, you do have to test for alkalinity.

 

I do bring my water in to be tested at the local fish store, Nitrates, Nitrites, and Ammonia are zero.

Testing for nitrate is fine. With a fully established nitrogen cycle, I wouldn't have them bother testing ammonia (and I never test for nitrite).

 

Which brings me to to the question of why Calcium needs to be dosed at all. I mean shouldn't water put the stuff in solution all the time...

Doppelganger explained this pretty well. The consumption rate of calcium (and alkalinity) of a tank that is stocked with stony corals can easily exceed the ability of 15% weekly water changes to replenish. Plus, weekly water changes result in larger swings than regular dosing of these elements.

 

Yep, I was just wondering how fast salt water could dissolve crushed coral and such. I would think it would tear it apart fairly quickly, but I guess you have quite a few other factors.

It depends on the pH. As the pH gets low, it dissolves more quickly; but it basically isn't dissolving with the pH at 8.2. Calcium reactors work on the principle of dissolving calcium carbonate, by lowing the pH with CO2.

 

Anyhow, I just got done with a 20 gallon water change. Um... er.. 15%. Hopefully that will cut the organics back and add some ions back into the mix... Anyhow, I guess I will do some more testing tonight and see what happens to KH.

Say your water contains 107ppm CaCO3 equivalents, and you do a 15% water change with water that contains 170ppm CaCO3 equivalents. That would be (107 * 0.85) + (170 * 0.15), which is 116.45ppm (and still way under what it should be).

[Bill_68]

Crap. I have supply the CO3 part of the equation too? I assumed that "Reef advantage calcium" was CaCO3 plus free ions of Magnesium ready to go with trace minerals.

 

Guess I will have to go get some "ReefBuilder" to go with it.

 

At least I got a better test kit for ALK Mag and Ca. Red Sea. Interestingly, yes - the API ALK test does agree.

 

I just wish these folks would include a few more little bottles and syringes. These things are a pain to use if you have big hands.

 

Anyhow, I did start building up Mg and Ca. I guess I will add some "ReefBuilder" tomorrow.

 

Thanks for all the comments. Helpful.

 

Bill