DKH dropped after using kalk.

[HAWK44]

I just started dosing kalk (Brightwell +2) via my ato (I know, not the best way but I’m saving for a ph controller and pump). I put a teaspoon in about 4.5 gallons of RODI with the ato. Before I started dosing a week ago my parameters were:

35ppm Salinity
Nitrate 0.00. (Red Sea test and Hanna checker)
Phosphate 0.06
DKH 7.2
Calcium 410
Mg 1520
PH 8.0-8.2

Just checked the DKH a week after starting and it is now 6.4. Checked with a Hannah checker three times and a Red Sea test twice. Exact same results between them each time.

I don’t run carbon. Have a skimmer rated for 110 gallons with a medium load. Only chemicals I am running is Two Little Fishies PhosBan.

Tank is a 24 gallon tank with a heavier bio-load from fish and a good amount of mixed coral in the tank.

 

[arking_mark]

Could the tank be consuming Ca/Alk faster than you're dosing?

 

[HAWK44]

I never had it drop like this before trying kalk.

 

[arking_mark]

How old is the tank?

 

[arking_mark]

How old is the tank

 

[HAWK44]

It’s been up and going for about a year and three months. I appreciate the quick replies!

 

[arking_mark]

How are you maintaining Ca/Alk?

 

[HAWK44]

Water changes every three weeks with Red Sea pro salt. I never really thought of it, as simple as it is, with all the coral in there it could be eating up the DKH. What’s weird though, I’ve always had low DKH in this tank since day one, even when I had a much smaller amount of coral in there, but never this low.

 

[GHOSTLY]

What coral? Could be consuming faster than your dosing

 

[Spieg]

What was the dKH before you stared Kalk, and are you still doing water changes? FWIW, I think dosing kalk via ATO is the worst method you could choose. What is your daily consumption of Alk?

From Brightwell;
"Instructions and Guidelines
Kalk+2 is intended for use by experienced hobbyists who are familiar with kalkwasser (calcium hydroxide-based) products. The calcium concentration (”[Ca2+]”) and pH in the aquarium should be determined by using an accurate test kit prior to supplementing. Do not add this product directly to an aquarium without diluting in water as directed, and do not overdose; it must be added in a controlled fashion with a dosing device. Create a stock solution by dissolving 6 grams (~1 tsp) of Kalk+2 in 1 US-gallon of fresh water (preferably purified) and allowing at least one hour for any settling to occur; each ml of the saturated sol’n will increase the [Ca2+] in 1 US-gallon (3.785 L) of water by 2.3 ppm, strontium concentration by 0.04 ppm, and magnesium concentration by 0.06 ppm. Decant only the clear solution into the aquarium. Discard any sediment. This decanted solution must then be dosed/dripped into the aquarium at such a rate that salinity does not fall below 1.021 g/cm3 and pH does not increase by more than 0.1 every hour, nor is it ever allowed to exceed a value of 8.5. Dosing at night when pH in a reef aquarium is naturally depressed is often performed to avoid exceeding the maximum allowable pH value. If the [Ca2+] in an aquarium is gradually dropping despite using this product as directed, the rate of evaporation may be insufficient or pH may be too high to dose sufficient calcium to compensate for the rate of removal by reef-building aquarium inhabitants and/or undesirable chemical reactions. In this case, a secondary calcium supplement may be needed to occasionally re-establish the natural seawater concentration of calcium in the aquarium."

 

[HAWK44]

I agree with the using the ato is a terrible method comment 100%. Like I said, getting a controller in for my pump in a week, hopefully.

Still doing routing water changes ever two to three weeks. DKH has typically stayed around 7-7.5 DKH. The coral have never shown any signs of anything but being happy, they all just grow a little slower. I have many SPS frags, a few LPS, and a mushroom or two.

 

[Garf]

A teaspoon full in 15ltrs is a tiny amount. You can increase it and monitor daily, till you get to the happy place

 

[HAWK44]

Sounds like a plan! I appreciate all the replies. While on the subject, does anyone know why I have unreadable nitrates? I feed mostly pellets and occasional LRS frozen food. Minimal algae. No coralline. Does this just happen from tank to tank or could it be a product of the heavy skimming?

 

[Randy Holmes-Farley Verified Community Expert]

I never had it drop like this before trying kalk.

One teaspoon per 4.5 gallons is very weak, and it is possible the increased pH (small here) will increase demand. I'd up the dose.

 

[Randy Holmes-Farley Verified Community Expert]

I agree with the using the ato is a terrible method comment 100%.

Terrible or not, I used it just fine for 20 years on my system and never felt any need to change it.

 

[Randy Holmes-Farley Verified Community Expert]

Sounds like a plan! I appreciate all the replies. While on the subject, does anyone know why I have unreadable nitrates? I feed mostly pellets and occasional LRS frozen food. Minimal algae. No coralline. Does this just happen from tank to tank or could it be a product of the heavy skimming?

Skimming is not typically sufficient to drive nitrate to zero, but having it that low isn't ideal and I'd either feed more or dose nitrate.