Precipitation in nano tank

[Galeno rocha]

Hi!

Here is my problem...

I have a nano tank 15 gallon with a 9 gallon sump.

At the moment I have mostly soft corals, two lps colonies, one of them small, and one montipora frag.

In preparation for adding hard corals i started dosing Alk for a while now.

My salt mix alk is 5 dkH. LFS keeps coral at about 4 dkH. I'm trying to keep it at 8-9.

I dose kalwasser at the top off water and use sodium bicarbonate to correct alk. Dosed at the return pump section of the sump.

My problem is: alk drops fast. Between 0.5 and 1 a day.

Yesterday two pumps stopped because of calcium carbonate deposition and I started noticing a white crust in the back glass.

Parameters:
Phos and no3: 0
Large refugium 11 hours almost reverse photo period.
Temperature: 83-84 F.
pH: 8.6. Used to be 8.4 but its rising slowly.
Calcium 325 last time I checked but I'm doubting the accuracy of my test kit.
Mg 1325. Dosed 100 ppm after that.

What should I do?
Lower refugium photo period?
Stop both kalk and nahco3 and go back tp water chanfes only?
I don't know how I could lower temperature.

I do want to solve the problem but would like to avoid a dip in alk at the same time.

Thanks for any advice.

 

[Katrina71]

I'd suggest stop dosing and do water changes to start.

 

[Galeno rocha]

The problem is that my salt mix has lower alk than my tank's.

 

[ReeferReefer]

Why not switch to a higher Alk salt mix to start?

 

[Galeno rocha]

The cost of reef salt where i'm from is very high. I can basicaly only afford this one brand.

 

[Cameron A]

84 degrees is pretty high most people run 77-80 degrees. High temperature can also raise the ph. I know they are pricey but you might need a chiller to lower that temperature.

 

[Galeno rocha]

Thank you. I'm thinking about it.
Unfortunately a chiller would cost more than the whole system and there are space constraints.

 

[Cameron A]

Is it just during the summer that you are seeing these high temps? If it is you could just freeze a water bottle or a bag of ro and float that in the tank.

 

[vetteguy53081]

What salt mix are you using?
Reef Crystals and Fritz coral pro have higher alk or you can use a liquid alk supplement with your current salt such as Brightwell Reef Code B or Seachem Fusion 2

 

[ReeferReefer]

A fan blowing across the water does a good job.

 

[Galeno rocha]

Is it just during the summer that you are seeing these high temps? If it is you could just freeze a water bottle or a bag of ro and float that in the tank.

No, it is year-round.
I live in a tropical climate and the temperature does not change more than 1 or 2 degrees between seasons.

 

[Galeno rocha]

What salt mix are you using?
Reef Crystals and Fritz coral pro have higher alk or you can use a liquid alk supplement with your current salt such as Brightwell Reef Code B or Seachem Fusion 2

bluecrystal reef salt.
Is it possible to fix the salt mix's alk with sodium bicarb? Would it precipitate?

 

[Galeno rocha]

What salt mix are you using?
Reef Crystals and Fritz coral pro have higher alk or you can use a liquid alk supplement with your current salt such as Brightwell Reef Code B or Seachem Fusion 2

bluecrystal reef salt.
Is it possible to fix the salt mix's alk with sodium bicarb? Would it precipitate?

 

[BeejReef]

There are a couple things it could be.. well, probably many, but a couple that I'm aware of.. lol.

1) I'm guessing lack of water flow where your ATO is dosing the Kalk. The return pump usually isn't going to agitate the water all that much. A small, $12, china powerhead somewhere in the sump can fix that.
2) It sounds like you're trying to adjust your water's Alk and Calc with Kalkwasser. Kalk is usually used for maintaining a desired level. It's possible to use it to gradually adjust your alk/calc over the course of days or a week, but it's real finicky and complicated. A lot of math involved in determining your daily evaporation and mixing and dosing appropriately
3) If you screw up at all, it's easy to fall into a cycle where you're dosing like crazy but DKH and calcium keep falling. It's forming crystals on the rock, in the sand, or on the glass and those crystals are sucking up more and more of what you're putting in. To end the cycle, you have to stop dosing for 2,3,4 days, determine your daily alk demand, and try again.
4) The numbers you're talking about for your LFS and your salt mix sound crazy low. I've never heard of anyone ever keeping an alkalinity of 5dkh. Stony corals would slowly dissolve. Are you sure there's not a mix up somewhere between meq/L and dkh? Maintaining an alkalinity of 4 meq/L would be about 11 DKH, higher than most, but within the realm of normal

 

[Galeno rocha]

Thank you for the long explanation.
For sure it was the third option.

My tank is not supposed to consume much Alk since I have few and small hard corals.

I was trying to raise Alk with HCO3, since the Kalk made little effect.

For the last three days, I stopped the bicarb, using only the Kalk in the ATO and the dKH have been keeping steady at 8. I'll resist the urge to dose anything more and see what happens.

Yes. LFSs water has 5 dKH. They keep mostly soft coral. Albeit I used an API kit, wich can be imprecise.

I have a little damsel in the return pump section. But as soon as i take it out, I'll try the fix.