Backyard Aquaponics
A place to discuss aquaponics

I read that silica is important for some pants, and that it would be valuable to test. Also that 30 ppm is recommended.

Is it possible to have too much silica?

I am using RICHGRO Natural Garden Lime to buffer pH, and add calcium. The product brochure advises 80% Calcium CaCO3, and 15% Silica (SiO2).

I'm not sure at what rate Silica is consumed, but by my calculations, 200g of this product will result in 30 ppm of Silica in my 1, 000L system.

Now that my plants are growing well, I am struggling to keep the pH up by adding 2 teaspoons a day of potassium bicarbonate, and recently 2 or more teaspoons per day (~15 grams) of Garden Lime.

Is this regular addition of products normal, and could excessive silica cause problems?


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regular addition of hydrated lime / bicarbs is normal to keep PH up.
im not sure at all about silica uptake, but its very likely that it will not be used a lot by plants and could build up for sure.

im not sure if hydrated lime has silica in it, but if you want to move away from those, either because you have too much calc / potass. in the system or you dont want to dose daily, then find a very small amount of limestone (or at last resort a piece of old concrete - not new as its stil leeching dangerous chems).

egg or other shells can also help at a very slow rate.

Hi I typically lurk here and pardon the necro thread bump but this is a good question and I stumbled on this thread from a google search while trying to find a buffer that includes silica with a nod to aquaponics specifically.

Silicon/Silica is essential for plant growth. A quick google search will likely lead to numerous cannabis related articles however there are plenty of other non cannabis related articles as well. basically plants use silicon to strengthen their cell walls leading to stronger healthier plants.

Silicon also balances nutrient uptake, phosphorous specifically but it also competes with the uptake of metals helping to prevent things like metal toxicity (iron, magnesium, etc).


From this wiki link https://en.wikipedia.org/wiki/Potassium_silicate


Horticulture
In horticulture, potassium silicate is used as a soluble source of potassium and silicon. It makes the growing medium more alkaline.

It is also used as a supplement (in conjunction with normal fertilizer) for the numerous benefits that increasing the availability of silicon compounds has. Silicon-containing compounds are valuable to a plant, and serve to support the plant. Stems thicken, the plant becomes more tolerant to drought and resists wilting, and the plant gets larger leaves and fruit (because the stem can support more weight).


all that said, i doubt highly silica builds up in a health AP system unless the PH rises to the point where Silica is no longer soluble which from memory is around 7.3? so if you keep your water in the 6.6-7 range the plants should happily devour the silica.

lime with silica in it should be fine for non fruiting pants. anything that fruits i would supplement potassium silicate during the flowering/fruiting stage. maybe alternate with lime.