Jump in ph.

[Cichlid Dad]

@Randy Holmes-Farley

So I'm running a 120 150 total volume reef.

I just installed an Apex jr
I'm doing my nightly routine, came home from work fed the tank frozen, dosed my AFR and added my daily ALK all after taking my water sample for testing.

20ml AFR
30ml soda ash.
5ml carbon dose

Tank parameters from test

Hanna
Phos .06
Nitrates 6.2
ALK 9.3
Salufert
Calcium 425
Magnesium 1425.

This is the question. As I'm entering today's test results I see my PH was 8.18 when I got home. 30 minutes later after dosing and testing Apex shows a jump to 8.23. what did I do to get this jump in a half hour?

Lights stay on in my refugium 24 hours a day
Lights on my tank are 12 on 12 off full power T5's

I'm trying to really learn how what I do effects my system.

Thanks in advance

 

[rishma]

Did you see the pH jump after adding 30 ml soda ash? The soda will cause and immediate jump in pH.

Also, why are you adding soda ash in addition to AFR? Just curious

 

[Miami Reef]

Prior to adding soda ash it was 8.18, and after adding it, it reached 8.23?

Am I understanding this correctly? Do you usually dose 30mL of soda ash?

Soda ash will increase pH immediately after dosing.

 

[Cichlid Dad]

Did you see the pH jump after adding 30 ml soda ash? The soda will cause and immediate jump in pH.

Also, why are you adding soda ash in addition to AFR? Just curious

In my system if I dose AFR to my ALk my calcium and magnesium will climb. If I dose to calcium my magnesium stays consistent along with the calcium. So that's what I do and make up ALK with soda ash. Having the apex now I guess I noticed the jump,

 

[Cichlid Dad]

Prior to adding soda ash it was 8.18 and after adding it you reached 8.23?

Am I understanding this correctly? Do you already dose 30mL of soda ash?

Soda ash will increase pH immediately after dosing.

You are correct after adding soda ash it jumped

 

[Cichlid Dad]

Thank you both, got my answer.

 

[Miami Reef]

You are correct after adding soda ash it jumped

Yes. That’s completely normal and to be expected.

FWIW you should base the All For Reef dose on alkalinity. Alkalinity is more sensitive to fluctuations and has a tighter range than calcium. Calcium kits aren’t sensitive enough for dosing.

All for reef is a bit calcium heavy, so when calcium gets too high, you can switch to just soda ash for a while until calcium trends down.

 

[rishma]

To add to @Miami Reef comments, AFR will have approximately 10% excess calcium for its alkalinity.

You are currently adding about 40% of your alkalinity with AFR (0.2 dKH) and 60% with soda ash (0.3 dKH). So you are over compensating for the excess calcium in AFR by quite a lot.

It is not tank dependent, it’s a relatively fixed ratio for all reef tanks with calcification. For each 2.8 dKH of alkalinity consumed, about 18-20 ppm calcium and 1-2 ppm magnesium are also consumed.

I agree with the method @Miami Reef posted above. I suggest it’s better to dose AFR based on alkalinity demand. Let the calcium drift up over time, then dose soda ash for a while and let it drift down. Or just let water changes help keep calcium in check. Corals tolerate a wide range of calcium and it has to get pretty high to cause any issues. I’ve had it up to 600 ppm with no observable problems.

If you really want to dose both daily, then it would be more like 45ml AFR and 5 ml soda ash.