Diatoms. Help!

[bry1105]

I think I've read every article & forum post on the world wide interwebs about eliminating diatoms and nothing seems to work. My tank is several years old and my single T8 bulb is only on for 4 hours a day. I have a quality canister filter and do 30% water changes every 14 days. My well water is very hard so I use sediment filters & carbon blocks to remove the big junk. Every water test I perform shows nitrate & nitrite reasonably low in the tank. I've been battling the diatoms for probably a year now...

 

[bud29]

What is your substrate? Is the tank planted? If the tank isn't planted, you could try to add something like chemi-pure which removes phosphates and silicates. If the tank is planted though, you generally do want some level of phosphates in your water.

 

[bry1105]

A little more info: it's 46 gallons, unplanted, and has white gravel (great for diatoms, eh?).

 

[bud29]

Do you have access to a water report or something that could tell you how many phosphates and silicates you have in your tap water?

 

[bry1105]

I've placed an order at Drs. F&S for a phospathe test kit and Chemi-pure Elite. I think this route is the only one I've yet to try.

On a slightly different note, I've read very contradictory things about how light affects diatoms. Some say too much light causes it, and some say a lack of light. Any thoughts on this?

 

[bud29]

I think that if you have super excessive photperiods it may contribute to the issue - how long are the lights usually on?

 

[bry1105]

See my initial post:

...my single T8 bulb is only on for 4 hours a day.

It's just a simple 24" 17W T8 daylight bulb. Nothing fancy and nothing I would think would put out so much light as to cause problems.

 

[Rivercats]

Diatom have to have silicates in order for them to exist. Once silicates are exhausted in the water supply then diatoms go away. Some substrates, but especially some types of sand substrates, can release silicates into the water for quite a long time. Also if your water supply has a large amount of silicates in it this will just keep feeding the diatoms. Chem pure elite is okay but next time try getting a product like PhosGuard that is strictly for removing phosphates and silicates in the water.

 

[bry1105]

Another product that gets loads of great reviews is Poly Filter. It appears to do basically the same thing as Chemi-Pure Elite except in pad form. If one were to use both Chemi-Pure Elite & Poly Filter, would the pad be placed before or after the Chemi-Pure? Another way to look at it is, is Poly Filter considered mechanical filtration or chemical filtration?

Rivercats, PhosGuard appears it would be beneficial in my situation as well, but as I understand, you only leave it in place for a few days and then remove. Because I have a canister filter and no sump, I prefer products that can remain in place for a longer period of time as I don't want to be opening & closing my canister that often.

 

[Rivercats]

I've been using PhosGuard since the early 90's and you don't have to remove it in a few days. I've left it in canisters for months. If using it for phosphate control it can be used as long as it keeps phosphate levels under control. If you use it for silicates it's no different. Put it in and you can remove it or change it out if needed during regular canister maintenance. The only time it needs to be removed in a few days is if phosphate levels are out the roof high and the amount of product used absorbs to it maximum and needs to be replaced if more phosphates need to be removed. It doesn't leach when full. Products like ChemPure and ChemPure Elite "can" be used up to six months but they are no different in the fact that when they are fully loaded they stop working be it 6 weeks or 6 months. It doesn't mean they will necessarily work and absorb for 6 months but can just as PhosGuard can. And actually as long as PhosGuard is working regardless of time it can be left in a filter. Last spring we added a pond size amount to the pond filter and removed it this spring. Once full it just acts as a media for BB to colonize on.

 

[bry1105]

Thanks for the additional info on PhosGuard. I've already got some Chemi-Pure Elite on the way, but if it doesn't provide the results I'm hoping for I'll definately try it.