I'll try to get readings tomorrow, for sure.
I currently have five girls in a 15g tank, no other fish species. Last week I had seven, but one died of dropsy and these other two have ended up with fatal, non related wounds today. Silk and plastic plants, smooth ceramic caves and large green glass jars make up most of the decor. Bottom is bare. I admit the filter is somewhat strong and I've tried to baffle it, but it hasn't held. It is an AquaClear 20, set on low. Lighting is a standard (forget what wattage, it's lasted for over two years and the box is long gone), although I don't keep it on during the day and only then for photos and feeding. Heater is a 15w Fluval M, set to 80*. I do 25-50% water changes a week, clean every surface, check the filter. Scrub algae. Food is Omega One betta flake and pellets, New Life Spectrum pellets and Grow, frozen blood worms, glass worms, brine shrimp, daphnia, defrosted shrimp meat and shelled pea on occasion.
I will get pictures tomorrow .... This is all I can offer for now, TL. Thanks for helping me figure out what's going on.