Alk Levels and Affect On Other

[7237689918]

Hi.

It's hard for me to get this straight.

If I run Alk lower (say 7.5) how does that affect, if at all, target levels for CA, MG, NO3, and PO4 in comparison to say running Alk at 8.5?

Thx!

 

[Ron Reefman]

It really doesn't affect them. But it works best for your corals if the Ca is at a balanced level to the alk level. Try running this calculator and it may help. Plug in numbers and raise the alk level and in the notes it will tell you what a balanced Ca level should be.

Reef Chemistry Calculator

Alk really has no effect on No3 and PO4. And Mg should be about 1300 or higher, but it doesn't need to be balanced to alk.

 

[Daniel@R2R Verified Admin]

Isn't it better to run lower alk on ulns? My understanding is that ulns can have issues with high alk?

 

[Randy Holmes-Farley Verified Community Expert]

Yes, coral skeletons may grow faster than tissue can keep up at low nutrients and high alk. 7.5 dKH can be ok with lower nutrients from that perspective, but low nutrients risks dinos.

I don’t think the alk level has any substantial bearing on optimal ranges for calcium and magnesium.

 

[blasterman]

I know plenty of SPS keepers that run alk in the ~7 dKH range. Only reason I prefer higher is alk can be depleted unexpectedly fast due to biology changes and once you start getting below 7 some hard corals can stress. Being stable is more important than higher/lower.

I've also had better luck keeping mag higher than 1300. Just don't use instant ocean if that's the plan (lol)

 

[7237689918]

Yes, coral skeletons may grow faster than tissue can keep up at low nutrients and high alk. 7.5 dKH can be ok with lower nutrients from that perspective, but low nutrients risks dinos.

I don’t think the alk level has any substantial bearing on optimal ranges for calcium and magnesium.

Thanks Randy.

I keep NO3 between 5 and 10, and PO4 between .05 and .1. At least I try to. Was thinking of keeping Alk between 7.7 and 8.2. I don’t chase exact numbers, mostly as I’m not good at it, but just shoot for those ranges.

Hopefully, they are decent and provide a good env for healthy corals.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks Randy.

I keep NO3 between 5 and 10, and PO4 between .05 and .1. At least I try to. Was thinking of keeping Alk between 7.7 and 8.2. I don’t chase exact numbers, mostly as I’m not good at it, but just shoot for those ranges.

Hopefully, they are decent and provide a good env for healthy corals.

Those seem like fine target values. [emoji3]