Thanks for the comments, they both are helpful.
I do use CaSo4 and also wondered if that contributed to the scratching. Between the CaSo4 & MgSo4 , KSO4 I often wondered if there is too much sulfur in my tank water which seems to me would be slightly acidic & could cause fish to scratch. I have been mixing my own Gh booster from planted tanks fertilizer instead of Seachems Equilibrium. My Gh is 5 Kh 3, TDS 200, Ph slightly alkaline. Maybe I should switch to a chloride. Has anybody else had similar experiences with the sulfur version when mixing booster?
I know there is sulfur even in the trace mix which would even add more sulfur.
I am going hunting with the microscope again today to see if I can find something but that is hit & miss. I feel it is more chemical than parasitic since it happens after water changes mostly.Thats why I felt maybe it was some chlorine getting past the membrane.
And yes I should replace my carbon soon as possible. Im thinking of switching to .5 micron carbons.
The question now is , should I switch to a chloride base booster???? Probably would not hurt. I have read that too much chlorides is bad for plants although I also read that is not true as well. Any further info would be great, thanks.
Well I'm not exactly stating the CaSO4 is a problem, it's just an observation I've had over the years. It usually happens if I'm adding quite a bit of the compound, e.g., when I'm doing a reset (99% +) WC essentially going from 0ppm TDS to over 150~250ppm at once. I've never lost a fish due to it and if I remember correctly it was't all of them that would do this, some were more tolerant to this than others.
If you are changing 20~30% of the water you shouldn't be much of that flicking that they do going on. What percent WC do you do?
Using CaCL2 they say will cause a problem over time due to build-up, so I would do a 50/50 mix over straight up CaCl2
forgot to mention gallons used by the membrane. I am really bad at keeping track of that. I had the membrane & all the filters changed back last June. I have been testing the membrane & 23 is consistent with rejection in the process water. I was not using much water out of it until August when I got back into the hobby again. I usually replace all carbon 1 time a year when only using for drinking , but I plan on 2 times a year for carbon & just keeping an eye on the membrane . If it climbs over 25-30 range I will replace it. But keep in mind I am not running a resin stage at the end & without it I have very hard water & to expect 0 for a reading is not possible.
They say to get the 10,000gals 0.5~.6 micron is the way to go, and ~3000gals for those 5 micron blocks. I currently use 2 5 micron Carbon Block and have put about ~1500gals through them and still no Chlorine present. I do have .06 Micron blocks, but have not have the need for them yet.
If you barely put any water through it even though it's been sitting I wouldn't worry about it. Age is not the factor, it's the gallonage that depletes it.