Problems with raising alk.

[RogueGrown]

Last week I tested my alk and it was low at 6.1 KH. I dosed 2.5 ml of alk tested the next day nothing changed so I bumped the dose up to 4 ml. I keep adding alk and it is barely rising. A week later I’m still only at 7 KH. I’m using flucal alk as it all that was available locally and have never had a problem raising the KH with it before. Any ideas what keeping it from going up? I’d like to raise it so I can begin using kalk.

Btw my tank is a 20g with a volume of about 14 gallons of water.


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[Tripod1404]

What is your Ca and Mg levels? if the ratio of these 3 are off balanced, alk (carbonate) will precipitate as calcium carbonate or magnesium carbonate.

[RogueGrown]

My mg is at 1400 and cal 440. I tested alk with 2 different kits and both read the same


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[nereefpat]

Yes. Good idea to check the other two levels.

Could be the tank is just consuming it though. My guess is that you just need to keep dosing

[Tripod1404]

Originally Posted by RogueGrown

My mg is at 1400 and cal 440. I tested alk with 2 different kits and both read the same


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Do you have any corals? If yes, they might just be using it.

[RogueGrown]

I have corals yes, but doesn’t that seem excessive though? Should I just start using kalk and slowly up the dose till the levels are where they need to be and then level it off?


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[ktownhero]

Did you start running GFO? I heard it drops Alk.

[RogueGrown]

Originally Posted by nereefpat

Yes. Good idea to check the other two levels.

Could be the tank is just consuming it though. My guess is that you just need to keep dosing

I guess what worries me is the instructions on the alk bottle say 10 ml per 50 gallons once a week for .5 DKH.... my 15ish gallons have had that in a week and I don’t see but 1 KH difference.


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[sde1500]

Originally Posted by RogueGrown

I guess what worries me is the instructions on the alk bottle say 10 ml per 50 gallons once a week for .5 DKH.... my 15ish gallons have had that in a week and I don’t see but 1 KH difference.


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But this doesn't take into account any drop by coral usage I'd assume.

[RogueGrown]

Originally Posted by sde1500

But this doesn't take into account any drop by coral usage I'd assume.

Do corals really consume alk that fast? My cal hardly moved it seems like.


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[RogueGrown]

Should I just start dosing kalk at this point?


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[Tripod1404]

Yes corals can use large amount of alk. Your water volume is low, so consumption would be very rapid. That is the main issue with small tanks, achieving stability is hard. If you have coraline algae, the consume alk as well.

Kalk will raise Ca as well as alk. Since you said your Ca is not dropping, dosing Kalk will spike the Ca.

Also keep in mind 1 dKH is roughly equal to 18ppm of carbonate. So if we assume 1-1 Ca/Alk consumption, your dKH would need to drop subsequently for you to see a big drop in calcium.

[RogueGrown]

Originally Posted by Tripod1404

Yes corals can use large amount of alk. Your water volume is low, so consumption would be very rapid. That is the main issue with small tanks, achieving stability is hard. If you have coraline algae, the consume alk as well.

Kalk will raise Ca as well as alk. Since you said your Ca is not dropping, dosing Kalk will spike the Ca.

Also keep in mind 1 dKH is roughly equal to 18ppm of carbonate. So if we assume 1-1 Ca/Alk consumption, your dKH would need to drop subsequently for you to see a big drop in calcium.

Dosing kalk could be a disaster than it seems. I did have coraline growing and not gonna lie got lazy and watched to fade away, I would like to get it back in check and keep it stable. Before I was just doing a 2 part system but would really like to go to kalk if I can.


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[RogueGrown]

How do people run kalk if alk is driven down so quickly?


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[ktownhero]

Originally Posted by RogueGrown

How do people run kalk if alk is driven down so quickly?


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Kalk is balanced Alk and Calcium. That said, you always want to have 2 part around to make adjustments as-necessary.

[RogueGrown]

So dose kalk lightly to keep calcium in check and use liquid alk as needed. Thank you


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[Tripod1404]

Generally you first reach your desired alk and Ca values with 2 part and then dose kalk to keep them at that level. When one deviate from desired values (since in reality, consumption is not 1 to 1), you use 2 part to correct it.

[homer1475]

Why buy ALK supplement when its so easy to DIY?

297grams of baking soda dissolved in 1 gallon RO/DI.

Then use this calculator to figure out your dosage.
http://reef.diesyst.com/flashcalc/flashcalc.html

Choose Randy's Recipe 2 Alkalinity part from the dropdown.

[RogueGrown]

Originally Posted by homer1475

Why buy ALK supplement when its so easy to DIY?

297grams of baking soda dissolved in 1 gallon RO/DI.

Then use this calculator to figure out your dosage.
http://reef.diesyst.com/flashcalc/flashcalc.html

Choose Randy's Recipe 2 Alkalinity part from the dropdown.

I didn’t realize it was that easy to make alk yourself, I’ll have to start doing this. If my tank is consuming alk at a high rate and my calcium is staying where it should I probably don’t want to go to kalk until I have a larger tank set up.

So is kalk a 1 to 1?


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[der_wille_zur_macht]

Kalk is very close to the right ratio for most tanks.

If you appear to have low alkalinity and/or trouble raising alkalinity - yet, calcium and magnesium are correct - then my first step would be to verify the measurement methods. Try other test kits for all three or borrow from a friend, or bring a sample to an LFS. You shouldn't really need to dose a ton of one and not the other on an ongoing basis.

Another strategy would be to do a handful of larger water changes over a few days, with a salt mix that has close to the correct ratios. Sometimes, this is the "safest" way to reset a tank's parameters. Otherwise, as mentioned above, you can dose 2-part to get to the right values then switch to kalk. Typically what I like to do is use kalk in place of topoff water, and start with a low strength mix (say, a teaspoon or two of powder per gallon). Then, test every few days and up the powder dose to get where you need.

[Redseadragon12]

Kalk is not nearly enough to support my tanks uptake of calcium or alkalinity. A better method is to dose 2part.

[der_wille_zur_macht]

It's hard to make sweeping statements like that. I've been keeping reefs for a long time and have maintained everything from FOWLR to stuffed-to-the-limit SPS tanks with nothing but kalk. I've also used two part (and calcium reactors), but never because kalk couldn't keep up.

There are a lot of reasons to use two part, but I don't frequently see situations where kalk couldn't keep up, other than odd cases - usually situations where a tank has very low evaporation, which is really the only limiting factor when it comes to how much kalk you can dose. Even in those situations, there are other steps you can take - do things to increase evaporation (which is often desirable since it's basically free cooling) or increase the kalk strength by spiking it with vinegar (which is often desirable since it's a source of carbon dosing).

[xCry0x]

People's experiences are always interesting.

My tank isn't overly stocked with coral and only a few smallish sps colonies. At about 50g of actual water volume I am consuming 100ml/day of both BRS CA and ALK 2 part -- which I found to be a staggering amount.

But the numbers don't really lie -- testing alk daily while getting my doser going things didn't stabilize until I bumped all the way up to 100ml/day. Was consuming about 2-2.5 dKH daily.

[der_wille_zur_macht]

I feel like there's this base assumption that calcium and alkalinity uptake is associated with SPS and other stony corals. IME that's not strictly true. Many SPS are so slow growing that they don't really consume a ton, in the relative sense. I've had tanks with zero coral that consumed significant quantities of both - usually thanks to coralline algae growth.

Even softy-dominated tanks can have high demands - softies can grow very fast (in terms of biomass increase) and although they don't have a rigid skeleton, many do contain sclerites that are grown from calcium carbonate, just like an SPS's skeleton.

[Reef Bass]

4mls of alk supplement is a small amount. I am currently dosing something like 75mls a day, though my tank is larger. At my peak demand was 300+mls per day.

There was one reefer here who needed to dose over 900mls per day. His tank was large with many stony corals. And they looked good!