At the top of my tank and the glass below the light. There is a white crusty stuff. I'm sure it is fine but i want to know what it is

Im thinking salt. If you have salt in your water, and the water evaporates, the salt leaves a residue because salt doesent evaporate.

no salt.

Hmm... Well I think condensation may also leave a residue because it dries and stuff. Just wipe it off with a wet cloth, its no big deal really. Tell the triple s crew I said hi!

Technically, Esareh is correct!

Although, it isn't exactly regular salt. Its calcium carbonates, magnesium and some other "salts". It's actually a sign that your water has a good KH (wich will hold your pH rock steady). Nothing to really worry about, Just wipe it away with a damp cloth monthly. Whatever builds up on the glass can be scraped off with a window scraper/straight razor.

I have to hit my glass tanks up every now and again because my water has a good KH (160ppm).

Hope this helps!

Its calcuim build up easy to get off with a razor blade or tank the hood off and soak it in vinager for a few hours and scrub gentle then rince well to get off.

It wont hurt the fish the white stuff

Always its vinegar! lol why not perfune?

woah...i like hte smell of vinnegar! we use it all the time at the barn for cleaning!

Vinegar reminds me of easter and dying all those eggs every year!

Vinegar reminds me of aquarium sealant. Mine smells EXACTLY like vinegar

vinegar burns my nose, but it is good at cleaning stuff. I find that that stuff could be calcium carbonate as it is already said. Because our water contains many minerals.

I knew it wasn't harm. I tried getting it out with plain water but i had to scrub it hard. Thats good it is a good sign my ph is rock steady. Does that mean the ammonia and nitrites and nitrates are steady

Nope. kH and pH have nothing to do with ammonia, nitrite, and nitrate. You have to test for that.

As Phreno mentioned, ammonia, nitrItes and nitrAtes are different than pH, KH and GH. For a good description of what happens when your tank is cycling, read this page: Cycling tanks.

For a good description of what pH, KH and GH are and how they are related, read this page: pH/KH link


I hope this helps you some, if you have any questions, don't hesitate to start a post in the water chemistry forum.