How much should I chase ALK?

[Eyedogtor]

Hello,

I have a 190g reef tank that has been up for about 10 months. Everything is looking great (SPS, LPS, Zoas, etc.). I dose aquaforest 3 part, and do continuous water changes through my Apex/DOS pump - about 1 gallon per day. My challenge is that my ALK is low - 6.8. CA is 415, MG is 1400, Phos is 0.03.....not sure how much I should 'chase' this low ALK vs. just observing talk progress as a measurement?

Thanks for any advice - and here is a video of the tank as an example.


Pat

 

[Mastiffsrule]

Hi,

You don’t want to chase numbers but you do want to keep them balanced and within a range. Your calcium looks good at 415. I would try to bump it up to 420-440 range. To keep alk balanced you should be in the 8.4 to 8.6 range. Your mag is good right where it is at. If you could get you numbers in that range you can dose calc and alk 1:1 and you should be good. Don’t try to stay at a number. That is why I put a range.

Po4 at .03 is good with No4 around 5 to 10

 

[rogersb]

I like alk between 7 and 9. Today I tested and it was 8.4. Last week it was 7.2. I top off with kalk and use arm and hammer if the kalk isn't giving me enough. Being rock solid isn't so important as being within an acceptable range. IMO below 7 is not acceptable.

 

[Duncan Tse]

If everything is looking fine I would just stay where you are at.

If you feel like alk is low then I would just bump up your 2 part by a little bit each week and then test again the following week and see where your numbers stabilize at.

IMO other than your alk, your parameters look fine to me.

 

[Vette67]

Alk at 6.8? That’s barely low. A couple teaspoons of baking soda will fix that. Now, my alk was low....

But Alk is very easy to correct with baking soda.

 

[Fishingandreefing]

Kalk in ato, I try to keep mine at around 8.5

 

[fishguy242]

slowly bump both cal and alk on different days alk,cal,alk,etc go slow and steady corals are fine no hurry

 

[sawdonkey]

Alk is the ONE thing that I really focus on. I wouldn’t say that I chase a number, but I shoot for around 8.0 and I’m happy if it’s between 7 and 9. I’ve had my alk drop down to the low 5s and also has it shoot to 10 without losing anything. I surely wouldn’t recommend big swings though.

 

[Crustaceon]

I don’t think you’re far away enough to warrant chasing alk. The most i’d do is slightly increase just your daily component 2 (alk) dose. Test each week and add a little more if needed. You don’t have to be in a hurry since your corals are happy. Just take it slow and see how they do at 7dk first. Hold it there for a few weeks. If you see improvements in growth, bump it up little more or leave it as is. My system runs well at 7.4dkh and that dang garf bonsai finally decided to start moving.

 

[hart24601]

I personally wouldn’t touch it, numbers look good to me. Plenty of people keep alk around 7, I wouldn’t let it fall any more, but if your system is happy 6.8 to 7 then rock out! Many people do far more damage fussing with numbers.

 

[vetteguy53081]

Bring it up Gradually. Wouldn’t hurt to take a water sample to a trusted LFS and have them test water for you and verify the results and to compare with yours

 

[Eyedogtor]

Thanks to everyone for the help and advice. Just sent a sample to ATI (I do that every quarter) and I'll confirm numbers, and then start to gradually bump up. Thanks again!

Pat

 

[radsdad]

I'm curious as to what salt you are using?

 

[Eyedogtor]

I'm curious as to what salt you are using?

I'm using Aquaforest salt - but open to trying others (with this tank, I've always used Aquaforest).

Thanks,

Pat

 

[litenyaup]

That alk is on the low side. I would recommend either dosing or using kalk in line with ATO. That will both bring up you’re alk as well as calcium.

 

[deerhunter06]

id say its more along the lines of what it started at and how its going down. If its maintaining with what you are doing then it should be fine. If you are depleting your alk with what you are doing then bad things will follow. Its all about consistency.

 

[Eyedogtor]

Well, I baked some Baking Soda and then added 8 oz of a solution made with that to the tank over a couple of hours - and now I'm at 7.3. We'll wait a week and see how things stabilize. Thanks for the advice all!

 

[Wescalland]

Alk at 6.8? That’s barely low. A couple teaspoons of baking soda will fix that. Now, my alk was low....

But Alk is very easy to correct with baking soda.

I use the same Hanna alt tester and was consistently testing very low - turned out it was a bad batch of the reagent. LFS tester my water and all was 10 when Hanna was testing about 4-5 - worth checking if you suspect it’s testing low! Hanna sent me a new bottle of the reagent for free, no problems now.

 

[Stealth91rt]

Well, I baked some Baking Soda and then added 8 oz of a solution made with that to the tank over a couple of hours - and now I'm at 7.3. We'll wait a week and see how things stabilize. Thanks for the advice all!

I find it easier to not bake it and use a scale with the BRS calculator for sodium bicarbonate to adjust alk. The only time I would bake it is if your having issues with low ph. I will adjust by adding it to my ATO so its slowly added to the system while I keep my other dosing stable.

 

[Vette67]

I use the same Hanna alt tester and was consistently testing very low - turned out it was a bad batch of the reagent. LFS tester my water and all was 10 when Hanna was testing about 4-5 - worth checking if you suspect it’s testing low! Hanna sent me a new bottle of the reagent for free, no problems now.

That picture was from when my tester was brand new, my first test. I was blissfully reefing along for years, not really knowing what my parameters were. I had excellent acro growth, so I thought I had things under control. So I was slightly surprised when I saw that number. I slowly brought it up with sodium bicarbonate, and then used the checker to tune my calcium reactor better. Now things are fine and I run 8 - 8.5 consistently. I am on my 4 th bottle of reagent, and I believe that number was accurate.