don't forget to test alkalinity

[Sk8r]

One of the most overlooked things when you take to 'shroom culture is testing beyond just nitrates and ammonia.

Shrooms are pretty tolerant of nitrates. They don't mind water that a lot of corals don't tolerate.

What really sets them off:
1. ph out of whack. Should/be 7.9 to 8.3. A meter is the best way to read that.
2. alkalinity out of whack. S/b 8.3-9.3.
3. salinity out of whack. I keep it at 1.025, which gives me .001 leeway in either direction. One of the best investments you can make is an autotopoff float switch and a bucket of ro/di. This means instead of your having to add a lot of water at once to keep your salinity 'on', this dandy little switch turns on a pump to add a tablespoon of water---as needed. Corals of every sort like stability, and if you're ALL soft tissue, like a shroom, salinity changes 'hurt'...because your tissues are getting either pickled or flushed with too-fresh water. Make those changes as small as possible and your shrooms will be happier...and an autotopoff also lets you go away for days and know your tank will be perfectly balanced when you get back.
4. trace elements---do your weekly 10% water changes faithfully and despite the fact that shrooms don't mind particulates or slightly 'dirty' water---your shrooms will be happy with the water change. Why? Your salt mix contains much, much more than just salt. It contains all the trace elements [tiny, tiny fractions of elements like selenium and thorium and so on] that your shrooms 'eat up' during the week. It also, and incidentally, keeps your calcium, alkalinity, and magnesium in balance: you don't have to fuss with the Great Triad as much with shrooms as you do in stony corals, but let me just reveal a secret of the coral universe here: if these three aren't in balance you can dose alkalinity buffer or calcium until the cows come home and it will do no good. That salt mix has these three in good balance, and if you do your water changes on schedule, you will not have the problem of making them balance.
Should you discover you CAN"T make them balance, I [or any stony coral reefer] will be happy to tell you how, but usually, with shrooms, the salt mix is enough. [And just in case you intellectually wonder, it's this: the magnesium needs to test 3x where you want the calcium to read---so if you have 420 calcium, you want the mg to be around 1300; and if you have 420 calcium, 9.3 alkalinity is a great reading: it can be higher; it can be as low as 8.3. If you have those readings, they will not be shaken out of stability until corals eat enough of one of them.] But that's magically what your salt mix takes care of---mushrooms are modest consumers, so you mostly don't have to test those, so long as you keep those water changes going.

Hope that helps.