Sea lettice causing huge swings in CA and DKH?

[bestfishes]

I run a 125g mixed reef with some stoneys and lots of soft corals. I recently added Ulva sp commonly referred to as sea lettice to my refugium for nutrient export. Since it has started to grow out, im noticing huge drops in CA and DKH on my trident, causing me to up my dosing to more than double of what I was using before (DKH normally 100ML per day now up to 250 and DKH drops to low 7s every few hours, normally 35ml for CA now 75-100 per day) . I decided I was tired of chasing this and so removed the lettice today to see if I can get things to stabilize. Has anyone ever heard of plants like this absorbing so much CA/DKH? Or is this a red herring and im chasing the wrong solution to my problem?

 

[Randy Holmes-Farley]

Ulva does not consume or directly alter the calcium or alkalinity. I’d look for a different cause.

It may raise pH a bit which may boost demand a little.

 

[MrGisonni]

I agree, the Ulva is not a calcareous algae so should not impact alk or calcium.

 

[bestfishes]

Thanks for the responses. My next step has been to clean the cuvette of the trident to be sure my test results are accurate. If that does not stabalize my DLH and CA, any other suggestions?