Leaching rocks

[rocksmom]

Wasn't sure where this would best be placed, but I settled on here since I think it's affecting my water parameters.

I bought various sized river rocks from a local landscaping place to use in one of my tanks. They're a dark gray with no veining or anything. They passed the acid test, but the TDS in my tank is crazy high. My tap starts out at a little over 400, which I know is very high to begin with, but my tank had reached over 900! That's with regular water changes and very light fertilizer dosing. After a couple large WC I have it down to about 700 right now. I'm pretty sure the rocks are to blame because they have a weird substance growing on them. It's dusty looking like diatoms, but a dark reddish color. My otos and ramshorns won't touch the stuff either.

All the inhabitants seem fine. The only death I've had is one new amano that I had just added to the tank.

So I guess my questions are:

Any idea what they might be leaching?
Should I remove them?
If I leave them in, should I counteract by using straight RO for water changes?

Thanks!

[Psycofc1]

Any idea if the reddish color may be rust? If so yank them quickly

[rocksmom]

Originally Posted by Psycofc1

Any idea if the reddish color may be rust? If so yank them quickly

Thanks for the reply. I'm not sure if it's rust or not, it's not the typical light orangey-red color. I got a picture in case that will help.



Sorry the picture's so dark. It's about the same color as the darkest shades on the red tiger lotus. I really hope I don't have to remove them. The tank is full of them and it would probably cause an ammonia spike as well.

[rocksmom]

I put another light on the tank and got a better picture, but while I was looking I noticed a couple of the smaller rocks do have rust colored spots on them.





So I'm guessing they all need to go?