Alkalinity question in relation to PO4

[DDenny]

I have been watching my alkalinity, Ca, and PO4 like a hawk trying to get things dialed in. For the last two weeks I have had to dose Randy’s recipe #1 Alk part at 5.2ml daily as Alk consumption was .4-.5dkh daily. Started a small refugium with chaeto about three weeks ago to help with pH 7.9-8.0 every day without fail. It has also brought down my NO3 to 10-12 and my PO4 was holding steady at .08-.1. Everything was working great.

I didn’t want to bottom out nutrients with refigium and I had NP Bacto Balance so I dosed the 0-1 year old tank amount (.18ml) for two days and now my PO4 is indictable and NO3 is still at 10. But my dog consumption has dropped to .1dkh per day where it used to be .4-.5dkh drop per day. I’m confused I also thought that NP Bacto Balance was supposed to maintain no3 and po4. Dropping by LFS to pick up some Seachem Flourish phosphorus to slowly raise the PO4.

If I get PO4 back to .08-.1 will alkalinity consumption go back to what it used to be?
Here are my current levels
Salinity 35ppt
PO4 undetecable
NO3 10
Ca 430
pH 7.9-8.0
Alk 8.5dkh

 

[Timfish]

There's multiple factors that affect growth of corals. However, if they don't have enough phosphorus they are going to have difficulties trying to grow and it's not surprising to see bicarbonate usage drop.

 

[Randy Holmes-Farley]

I don’t know what explains everything you report, but Bactobalance is a bit of a black box product (secret composition) so explaining what it does or doesn’t do is tricky and I generally do not recommend such products.

That said, if phosphate is too low, I’d certainly dose some or feed more and that may impact alk consumption.

 

[DDenny]

I don’t know what explains everything you report, but Bactobalance is a bit of a black box product (secret composition) so explaining what it does or doesn’t do is tricky and I generally do not recommend such products.

That said, if phosphate is too low, I’d certainly dose some or feed more and that may impact alk consumption.

I did start feeding more and picking up so searched phosphorus here in a little bit to dose and bring it back up to .08-.1. Reduced the lighting on refugium to 8hrs vs 12hrs as well. Not going to use it anymore so hopefully that will not happen again. Thanks for your explanation.

 

[Northern Flicker]

I don’t know what explains everything you report, but Bactobalance is a bit of a black box product (secret composition) so explaining what it does or doesn’t do is tricky and I generally do not recommend such products.

That said, if phosphate is too low, I’d certainly dose some or feed more and that may impact alk consumption.

Do products like NeoPhos dose usable phosphates or do you recommend dosing something else?

 

[Randy Holmes-Farley]

Do products like NeoPhos dose usable phosphates or do you recommend dosing something else?

Yes, but what I recommend is food grade sodium phosphate. It is much less expensive than hobby products and comes with a purity assurance those lack.