How much Alk do I need?

JCOLE · Apr 20, 2019

Hello everyone. Trying to figure out this dosing thing.....

I transferred everything over to my new 150. I was using kalkwasser before and now want to get a handle on the 2 part dosing. I haven't dosed anything for 5 days and tested Alk everyday. Started at around 10dkh and it dropped 28 dog daily until yesterday. Yesterday it was 9.07 and today it tested at 9.02. I am using the Hanna checker.

My question how do I know the appropriate range to keep it at? Will it continue to go down from here? Why the 28dkh everyday and now the 5dkh today?

Sorry but this is part of the hobby that confuses me the most.

Hitman · Apr 20, 2019

Nitrates have a effect on DKH. The higher the NO3 the more it will lower ALK. It's one of the things I check if I get more then a 0.25 DKH swing during testing days and sure enough my NO3 has gone above 10ppm every time my DKH has gone down 0.25 dkh or more. I personally keep my Alk at 9.5DKH and have awesome growth with both SPS and LPS. Just remember the lower your NO3 and PO4 are the lower you should keep your Alk. With the levels I keep ( 5ppm nitrate and 0.03 Phosphate) my corals are happy, but if my nutrients went to zeros I would have burnt tips within 24 hours.

JCOLE · Apr 21, 2019

Hitman said:
Nitrates have a effect on DKH. The higher the NO3 the more it will lower ALK. It's one of the things I check if I get more then a 0.25 DKH swing during testing days and sure enough my NO3 has gone above 10ppm every time my DKH has gone down 0.25 dkh or more. I personally keep my Alk at 9.5DKH and have awesome growth with both SPS and LPS. Just remember the lower your NO3 and PO4 are the lower you should keep your Alk. With the levels I keep ( 5ppm nitrate and 0.03 Phosphate) my corals are happy, but if my nutrients went to zeros I would have burnt tips within 24 hours.

I did dose a little bit of Trisodium Phosphate and Sodium Nitrate twice this week. That would probably explain the drop?

I have some LPS, some rocks of Palys, and some frags of SPS. I wouldnt think they would be consuming that much but I could be wrong. I want to eventually switch over to SPS dominant but I am waiting until the tank stabilizes and I get this dosing under control.

Hitman · Apr 21, 2019

Depends on what lps you have but yes they can suck it up when your nutrients are on the high side, I know my hammers, frogspwan, and torches do.

Randy Holmes-Farley · Apr 21, 2019

Just to clarify, nitrate itself has no impact on alk. Consumption of nitrate adds alk and production from foods or ammonia reduces alk.

High ICP · Apr 21, 2019

Why are you adding nitrate and phosphate to a reef system?

That makes no sense

Randy Holmes-Farley · Apr 21, 2019

High ICP said:
Why are you adding nitrate and phosphate to a reef system?

That makes no sense

Lots of people need to, and benefit from, dosing one or both. Their levels are undesirably low without dosing.

PatW · Apr 21, 2019

I think ALK in seawater is about 7 DKH. Most saltwater aquariums run from 8 - 12. The big thing is to keep DKH as constant as possible. I have an SPS dominant tank and I run mine at about 8.1.