Alkalinity dropping, needs 72ml for a 55g tank?

[ketchup318]

Hi All

For my RSR 250, I am currently dosing 72ml/day of Alk. I also dose the same amount for Calcium, to keep everything balanced. I know it's higher than most people and I really don't understand why it is the way it is.

Originally after I got all my coral in, 6 months ago, I stopped dosing completely for a few days, did a water change and checked the Alk, it was at 7.5. I dosed to 8.0 and verified it was where it was supposed to be. I did this for 5 days, test before, dose, check after. Using this method, it said that I needed ~48ml a day. And that's where I set it.

I implemented this on my GHL doser and after a day, the 8.0 dropped to 7.0, even with the dosing. I manually add again, and test to verify. The next day the same thing; it drops to ~7.0. After a week, this trend doesn't seem to change. I still need to manually add more Alkalinity.

- I've checked the GHL program.
- Checked the reservoirs to make sure it's filled
- I've checked for leaks
- I've put a measuring cup under the drip tube and measured the amount dosed per day, and it's dead on

Magnesium is good, between 1300-1350. Calcium is reasonable also, 425.

I'm not sure why I'm using so much alkalinity. I don't have many corals
- duncan
- frogspawn
- daisy coral
- torch
- zoas
- montipora
- lepto

Any ideas?

 

[tgionet]

How long are you waiting between ca and alk supplementation?

 

[DSC reef]

What are you testing alk with?

 

[kyleinpdx]

go poke around your sand bed, if you find any hard spots its calcifying, you could be supersaturating the water causing the CaCO3 to cement it together. its my understanding that higher mag will help offset this.

also, are you experiencing a large increase in coralline?

 

[ketchup318]

My GHL doser is set to dose Alk on the hour and Calc, at the middle of the hour.

My mag levels are decent, 1316 from an ICP

I generally test Alk using a Hanna Checker, Calc & Mag with Red Sea test kits. I got to a point where I was so unsure of what I was doing, I sent my water for an ICP test. The alkalinity checks out with what I expected when I sent it.

No coralline whatsoever

If I'm super-saturating the water... how long do I need to wait to start the dosing process over? Do I need to replace the sand? Would using Kalk be more stable?

 

[cracker]

I also seem to be going thru a lot of alk with not that many corals here is a bump so maybe we can learn more.

 

[Bacon505]

Best if you do one part in the morning and one part at night.

 

[cracker]

Good advice but where is all the alk going? One thing I love about this hobby is that nothing works "exactly " how its supposed to ! LOL

 

[WesleyC]

Denitrification also lower the alk. Do you have a refugium or denitrator?

 

[Randy Holmes-Farley Verified Community Expert]

Denitrification also lower the alk. Do you have a refugium or denitrator?

Actually nitrification depletes alkalinity and denitrification adds it back (except a sulfur denitrator, which depletes it).

 

[Randy Holmes-Farley Verified Community Expert]

Magnesium is good, between 1300-1350. Calcium is reasonable also, 425.

I'm not sure why I'm using so much alkalinity. I don't have many corals

Assuming what you are dosing is my DIY (like from BRS), then you are dosing a tad under 2 dKH per day. That's not excessive, even in a soft coral tank, if there is coralline growth.

 

[WesleyC]

Thanks for the info, Randy. I read something about that from one of your write up. Just remembered it wrong.

 

[Lninwa]

I have always choraline but I heard once from Mr SWT that not every successful tank has it

 

[jordimex]

following

 

[saltyhog]

That's not terribly high. If you aren't having any precipitation on equipment or in the sand bed I would just adjust as needed.

 

[ketchup318]

Thanks for all the replies. I guess I'll keep dosing ml/day. Don't have any coralline growth, but also don't have any hard spots on the sand... so i guess it's a wash.

 

[splix]

coraline eats a lot more alk than you might expect. I was dosing like 100mg/day of seachem fusion into my 125. I was full sps and figured it was normal. My entire rear glass was completely covered in coraline. I then swapped tanks out for a new marineland since my old one was very old. Same coral, just no coraline. I think my dosing dropped to around 30mg/day.