read the links bud It seems that you have been using silicon incorrectly ....
http://www.growell.co.uk/blog/2013/11/food-for-thought-silicon-enhancements/
http://shogunfertilisers.com/products/silicon/
SILICIC ACID
Silicic acid is a weak acid that forms when Shogun Silicon is dissolved in water. It exists as this in solutions with a pH less than 7. Above 7, it dissociates into the silicate anion that can react with Calcium and Magnesium to cause nutrient solution clouding (see below on how important correct mixing is!).
Stable silicic acid in your nutrient solution can have a number of positive effects…
CORRECT MIXING IS ESSENTIAL!
If you want to see all of the benefits that SHOGUN Silicon can offer then it’s essential that you mix your solution correctly (as outlined in the above mixing instructions). If you don’t follow this order – for example if you add your nutirnets to the tank first and then add concentrated SHOGUN Silicon without adjusting your pH then you will see a plume of cloudy liquid appear as you add the Silicon. This will rapidly dissipate, but you’ve immediately lost some of the benefits of Silicic Acid (above) and have cause some of the Calcium and Magnesium in your solution to precipitate and “drop out” of solution. This is not a great idea and is very easily avoidable by adding your Silicon FIRST to plain water and then adjusting your pH to below 7 before adding your nutrients. The key point to recognize is that the pH cannot be above 7 when the Silicon and nutrients make contact. Follow this golden rule and your SHOGUN Silicon benefits will remain maximised.