Where and when do I test phosphates?

tzabor10 · Oct 2, 2023

This might be silly,
But when you measure phosphates and nitrates where and when do you pull water from? I get a big swing if I measure water from the top of the display and the effluent from the GFO reactor. Also get much different results from a feed cycle and the other days. What is everyone else doing?
Thanks
Tom

Reefer Matt · Oct 2, 2023

I usually draw next to the overflow. If I am due for a water change, I test at least an hour after it is done.

Pod_01 · Oct 3, 2023

I get my sample water from main display, same area top front right corner. I do it in the late evening once food and other things are settled in/ mixed in.

But interesting question, if water was collected from close proximity to corals would it be same / different?

EricR · Oct 3, 2023

Interesting question -- never thought about it.
I just pull all of my test water from the front/middle of my tank,,, but I only have 40 gallons.

As for when, I lean towards end of my water change cycle (meaning before water change) but really more just randomly whenever I care.

EDIT -- I agree with the other posts that say:
Same time of day when tracking a trend for any specific parameter(s)

Ef4life · Oct 3, 2023

Imo testing is best done in the most consistent way possible to ensure the most accurate, repeatable results.

That means testing at the same time every day/week whatever your schedule is. Take the water from the same area of the tank every time. If you test after feeding,don’t test before you feed etc.

Me personally I like to test on Saturday since it’s my maintenance day, I test in the morning before anything gets dosed to the system. Consistently the same time-ish +/- 1hr. This gives me data to see what changed, and if something tests off either retest, or do required maintenance to fix it. I typically don’t retest after maintenance/water changes, but do on occasion just to make sure everything is still good.

jda · Oct 3, 2023

Pull water out of the main display. The effluent from the GFO reactor should be lower if the GFO is not exhausted already, water was changed and the GFO is now unbinding po4, etc.

Propane · Oct 3, 2023

Same time same place from main display is what seems to work.

tzabor10 · Oct 3, 2023

Thanks,
Maybe I am not thinking about this correctly. I was considering whether to test the dirtiest part of the tank as well as return water. This way the range of phosphate is seen instead of trying for precision. Or do I have it wrong?

Snoopy 67 · Oct 3, 2023

Check water right out of the reactor against any tank water anywhere, because the tank water solution is basically the same.
The Difference between the 2 will let you know if the GFO needs to be changed.

Mr. Roboto · Oct 3, 2023

Most people feed too much. Feed 2 or 3 times a week and always draw water from the display before feeding.

DJF · Oct 3, 2023

Agree with the consensus of consistency and in the water column of the DT. If I am doing something that addresses phos/nitrate then I measure more often. I used to do them 1x wk but lately I’ve been testing Nitrate more often than Alkalinity.

Randy Holmes-Farley · Oct 3, 2023

Aside from the GFO reactor effluent, phosphate will be fairly similar everywhere.

Randy Holmes-Farley · Oct 3, 2023

Mr. Roboto said:
Most people feed too much. Feed 2 or 3 times a week and always draw water from the display before feeding.

I don’t agree with that statement.

Mr. Roboto · Oct 3, 2023

Randy Holmes-Farley said:
I don’t agree with that statement.

Respectfully agree to disagree

Randy Holmes-Farley · Oct 4, 2023

Mr. Roboto said:
Respectfully agree to disagree

Im not a fan of starving fish.

tzabor10 · Oct 4, 2023

Wait, I thought you meant feeding Corals 2-3 times per week. My plank auto feeder goes off 5 times a day. Do people really feed fish 2-3 times per week?

Mr. Roboto · Oct 4, 2023

Randy Holmes-Farley said:
Im not a fan of starving fish.

I havent ever had a starving fish so I wouldnt know what its like.

Randy Holmes-Farley · Oct 4, 2023

Mr. Roboto said:
I havent ever had a starving fish so I wouldnt know what its like.

IMO, it is misguided and potentially cruel to feed fish as infrequently as you do.

Do you eat only 2-3 times a week? Try it, then come back and say how it is.

Mr. Roboto · Oct 4, 2023

Randy Holmes-Farley said:
IMO, it is misguided and potentially cruel to feed fish as infrequently as you do.

Do you eat only 2-3 times a week? Try it, then come back and say how it is.

Do you think there is nothing in the tank for the fish to graze on? I mean who feeds the wild fish?