diatomaceous earth problems

[lumpypossum]

Hi,

I have a pool in France and have been sold some DE by an online pool shop. This product has given me no end of problems.

Please can anyone advise me if the following product is suitable for pool filter use?

CECA ARKEMA Clarcel DIT2R, CAS NO. 68855-54-9.

On the bag it says "Conforms to Food Chemical Codex” . This immediately set alarm bells ringing as this suggests that it is food grade. Looking at the spec sheet for the product it suggests that it is ok for pools.

As a secondary question what problems would occur if food grade DE was used in a pool filter as I have not been able to find this information on the web.

Thanks for your help

 

[JoyfulNoise]

Food grade DE is NOT calcined (heat treated at high temperature) and is therefore not crystalline silica but amorphous silica with organics still in it. The amorphous phase of silica is softer and more easily fractured than the crystalline form. Food grade DE will cause a mess in your pool - cloudy water and plugged up filter elements. True pool-grade DE CAN NOT BE USED IN FOOD. So, if the product says that it is suitable for food use, then it is not pool grade DE and you have mess on your hands.

You need to completely tear down your DE filter and clean it out as best you can. If your filter grids are plugged up with DE, then you may need to replace them if they can not be suitably cleaned. Plugged up grids will manifest as higher filter pressure. Once your filter is cleaned out and recharged with POOL GRADE DE, you can try to clear your pool by vacuuming up any remaining DE. You will need to watch your filter pressure and backwash anytime your filter pressure rises 25% above clean pressure. So if your clean pressure is 10psi (sorry, I'm use to English units) then you must backwash when it reaches 12.5 to 13psi.

Good luck,

Matt