Phosphate E and Alkalinity swing?

[Novicereefer]

Hi,

I think Phosphate E by Brightwell is a great product. It does what it says, but every time I dose it, I notice my sensitive corals (Acros and Torches) look upset the next day - loss color, polyps not as extended and in some cases just flat out die. This has been a consistent thing for a few weeks now and everything else is stable. I tested my Alk which has been around 7.8 (Hanna checker) then a few days later it was 6.8 and after a water change it's 7.4. Is this normal? Am I missing something? Is running a bag of GFO in my sump and Refugium a better option? I've upped my kalkwasser dosing to slowly bring it back up though. So we'll see

Update - just tested 2 min ago - it's 6.8 after it being 7.4 on Tuesday. I mean the only corals I see growing is my Setosa and Chalice so it can't be them taking it all up.

 

[Randy Holmes-Farley]

Are you tracking phosphate? What is it after dosing?

Lanthanum does have the potential to reduce alk if overdosed.

 

[Novicereefer]

Yes. Started at.37 then dropped to.24 then dropped to.19 then to.08 then to.02. Then I stopped using it. This was over the course of a week. In that time I lost 3-4 torches and basically my Acros all bleached. It wasn't until I checked my alk and saw that it was really low compared to what I normally run it at

 

[Randy Holmes-Farley]

The coral negative response may be from phosphate drop itself.

 

[Justdrew]

Yes. Started at.37 then dropped to.24 then dropped to.19 then to.08 then to.02. Then I stopped using it. This was over the course of a week. In that time I lost 3-4 torches and basically my Acros all bleached. It wasn't until I checked my alk and saw that it was really low compared to what I normally run it at

I would vote for the drop being too fast. Also think it went too low.