It works best incorporated evenly all throughout the medium anyway, so unless there was a very specific need to have it localized in those spikes or tablets, I'd just mix it in.
Now, for active hydro setups, these OC+ tabs might be interesting, but don't know about how they would do completely submerged.
You could do the same thing with OC+ regular prills and a tied-off stocking for less money and zero chance of the prills migrating.
Now, for active hydro setups, these OC+ tabs might be interesting, but don't know about how they would do completely submerged.
You could do the same thing with OC+ regular prills and a tied-off stocking for less money and zero chance of the prills migrating.