STS, high CEC, capping

[raharlow]

Looking for some advice and basic knowledge as it relates to Safe-T-Sorb, a high CEC Montmorillonite Clay substrate. I'm kind of cheap, plus I kinda like diy and off the shelf type of stuff, so I decided to try using STS instead of aquasoil. I've screened it (1/8") to get out the tiny stuff and plan on "pre-charging" it. What I mean by pre-charging, is add chemicals into some water to allow it to absorb the chemicals/nutrients, etc before I put into tank. If I put in the tank without doing this, it would strip away nutrients/kh from the water column. So, one of my big questions is what to charge it with and what order. Considering:

Baking Soda(NaHCO3) or Potassium Bicarbonate
KH2PO4
K2SO4 but maybe not if using Potassium Bicarb
MgSO4
Micro ferts
Dpta Iron or Gluc Iron

Next question is about capping. The plan is to put the STS in media bags (mesh is big enough to allow roots to penetrate) to prevent "mixing" and to cap with BDBS (Black Diamond Blasting Sand) which is inert. I understand that over time I may need to supplement the STS with root tabs and have considered using root tabs from the start, but unsure at this point. Are there negatives to doing what I'm planning on, and if so are there ways to counteract?

Thank you!!

 

[dw1305]

Hi all,

Looking for some advice and basic knowledge as it relates to Safe-T-Sorb, a high CEC Montmorillonite Clay substrate.

It should be fine. Have a look at my experience with <"moler clay cat litter">.

Baking Soda(NaHCO3) or Potassium Bicarbonate

I wouldn't use baking soda (sodium bicarbonate), the sodium ion (Na+) will be lightly bound (all monovalent ions are) and it <"will just be exchanged"> into the tank water. Same will happen with the potassium, but at least the K+ ion is a plant nutrient.

Next question is about capping. The plan is to put the STS in media bags (mesh is big enough to allow roots to penetrate) to prevent "mixing"

That should work. You could use it with capping.

BDBS (Black Diamond Blasting Sand)

I'm not keen, I don't like the colour, too sharp and angular, might contain metal residues (almost certainly doesn't) etc. If I was going to cap it I would use silica sand. "Pool Filter Sand" might be available to you?

I understand that over time I may need to supplement the STS with root tabs and have considered using root tabs from the start

I don't think you need root tabs.

cheers Darrel