mr. fix it

It's generally a bad idea to use straight tap water in a reef anyway. You have no idea what might be in it, possibly even copper from your pipes. Get an RO/DI filter. Well worth it in headaches saved.

I don't believe your test kit is accurate, as pH kits and monitors don't seem to read tap water correctly - at least the ones I've tried. Odds are your anemones are dying for other reasons, such as the pollutants in tap water.

What is the pH in the reef tank? What is the peak of the day, and the low for the wee hours?

i'm using melev's ro/di system with all new cartridges. i've got a milwaukee Ph meter, and a salt water master liquid test kit. i use red sea coral pro salt which i mix to a salinity of 1.024 with a refractometer. for a while my nitrates where high, so i was doing weekly 10% water changes, now thats back to normal. i've got a 50 gal tank that i use to age my salt water before i do my water changes in my 125 gal tank, with sump and an asm g-2 skimmer. i just kept checking my nitrates, because i thought that was the problem, but even the Ph in the 50 gal tank is around 9.1. so all my water changes were helping the nitrates and not changing the Ph. i just checked the Ph with the meter and it reads 9.0. thanks for your thoughts.

What are your water parameters? Nitrates, Phostphates, Alkalinity, Ph, Calcium... You should check these parameters first thing in the AM right before your turn the lights on and at night, right before you turn your lights off.

would a calcium reactor help to keep it down.

No, not in the sense you think it will. A Calcium Reactor with CO2 drives the Ph down inside the reactor to dissilve the calcium media. The amount of calcium that is released is controlled by the flow rate of water through the chamber as well as by the rate of release of the carbon dioxide bubbles. The dissolved solution increases alkalinity (carbonate hardness) to stabilize pH while replenishing minerals (trace elements).The CO2 lowers the pH in the chamber to an acidic level, which dissolves the calcium into the water.

i've got a milwaukee Ph meter, and a salt water master liquid test kit.

OK, How long has it been since your Ph probe has been calibrated and how old is your test kit. What brand liquid master test kit are you using?

Totally agree about calibrating your measuring devices, and recommend you take a water sample to your LFS or local buddy's home if he/she is in the hobby as well, to measure against your own numbers. I highly doubt you can maintain a pH of 9.1 unless you are dosing baked baking soda daily and are overdosing at that.

I'd guess a testing error as well. If that's not the case, club soda can be used to safely lower a high pH.