Diatoms

[loveittodeath_06]

I have read through the previous posts about diatoms but I still have a couple of questions. Is there anything, fish-wise/clean-up crew, that will eat them, and that my o's wont think are snacks? The diatoms started on the side of my tank between my glass and crushed coral and gravel where the sun shines, no where else. Even after vacuuming they come back with a vengeance and now are on my plants and glass bottles. I thought that diatoms where from not enough light? If so, why are they on the side that has no natural sunlight? My tank is 90 gallons and is about 3 months old and was an old saltwater tank that we re-siliconed.

[OinKY]

One of the prerequisites for diatom growth is nutrient content.Pretty much the main one.
Phosphates and silicates are the main ones involved.Any place those nutrients are concentrated will start diatom growth regardless of light level,just that usually in a higher light area they are outcompeted for the nutrients by algae.

It's possible that where the crushed coral is in direct sunlight it is leaching its mineral content faster. Since phosphates and silicates are capable of stratifying there's a good chance that that is a "dead zone" with little circulation.
Have you tried changing flow through that area by changing filter returns around or with a small powerhead ?
Also a good chance that this being a new setup with a recent reseal the problem will go away (in time) as the nutrients are used up.

I'm curious on the choice of crushed coral as part of the substrate. Are you trying to buffer pH higher ? If so,why ?

Far as something eating it,any fish that would touch it would be small enough to be O-Chow.That leaves snails...most of which that would actively prefer it (pond snails,some Ramshorn) are also O-Chow...which are "iffy" on it if something they like better is about. Apple Snail and Malaysian Trapdoor are large/tough enough around Os,but diatoms wouldn't be first choice on their menu.Some crustaceans....but crustaceans are way high on an O's menu.
It's better to find the cause than to make additions to band-aide it.

[loveittodeath_06]

The reason we chose the coral was because it was the substrate in my old mans family tank when he was a child and that it was 'help keep the ph constant' as he put it. Not to mention we got a deal and paid only $14 for 80lbs of it from a guy whom recently got out of his fish tank business. I am just at a loss when it comes to the diatoms take over! It seems like every time I do a water change that it just fuels them, and from what I read I probably does. So what do I do? Just let them take over and they will eventually go away, like I have read? They are just sooo ugly and I tend to take pride in my pets. As I always said I was and enthusiast, not a hobbyist, well at least until this happened! lol

[OinKY]

A water change fueling a diatom flair up would say there's probably phosphates and/or silicates in the tap water.
That can be tested for or simply request an analysis from the water company.Those analysis are handy to have anyway as it lets you know exactly (well,almost) what's coming out of your tap.

You can try a synthetic resin (or pad) for binding up phosphates and silicates and see if that helps.

The crushed coral is fueling the mineral content (which stabilizes the hardness)...but,honestly,unless this is used substrate then I can't see any minerals other than calcium and magnesium (plus some trace minerals) being leached.
The Ol' Man's correct on "helps keep the pH constant"...but that pertains to keeping it constant at a higher alkaline value and is only something needed if that's what you want to achieve. What's the pH of the tank ?...and what's the pH of the source water (tap,well,etc.) ?
Stabilizing pH is as easy as a water change...everytime you do your scheduled routine water change to eliminate nitrates you are also stabilizing the pH/hardness/trace minerals.