Low phos and low nitrate?

[BaileysTank]

So pretty much I love the look of caulerpa and made an external refugium and put some in, it grew 5 new “leafs” in 24 hours. Before adding it in both my nitrate and phosphate where at 4ppm now both have shot down to zero. Should I dose some nitrate and phosphate?

 

[blaxsun]

Refugiums can do that...

 

[gbroadbridge]

So pretty much I love the look of caulerpa and made an external refugium and put some in, it grew 5 new “leafs” in 24 hours. Before adding it in both my nitrate and phosphate where at 4ppm now both have shot down to zero. Should I dose some nitrate and phosphate?

How are you measuring Nitrate and Phosphate?

Macro Algae can use a lot, but they will normally just slow growth once Nitrate gets about 0.1ppm.

It's not a hard zero like you can do with Carbon dosing, or like a hard 0 phosphate with GFO or LaCl3.

If you dose, you'll just feed the algae - I'd just give it less light.

edit: It's also eating trace elements that could bottom out -and you probably want to avoid that. Like I said, less light.

 

[BaileysTank]

How are you measuring Nitrate and Phosphate?

Macro Algae can use a lot, but they will normally just slow growth once Nitrate gets about 0.1ppm.

It's not a hard zero like you can do with Carbon dosing, or like a hard 0 phosphate with GFO or LaCl3.

If you dose, you'll just feed the algae - I'd just give it less light.

edit: It's also eating trace elements that could bottom out -and you probably want to avoid that. Like I said, less light.

I give trace element supplants, I hassle use Hannah instruments but ran out of reagent so used API and I assume it’s probably very low just not 0

 

[Randy Holmes-Farley]

You can feed more, reduce the amount or lighting intensity or time on the caulerpa, or dose N and P.

 

[jda]

Don't worry about these numbers without getting a Hannah Ultra low for at least phosphate/phosphorous. Anything else is being blind.

The macro will slow down as the building blocks limit growth. IME, they never take it to zero or to dangerous levels.

You still likely have plenty of available building blocks for your corals even if your backend numbers are near to zero. This is no issue as long as you keep feeding your fish.

Iron is the only element that I have ever had to dose when growing massive amounts of macro. Products are made with manganese and other things, but I have never had to dose any of these. I do regular water changes, so that might be enough of the non-iron things.