Need lessons on substrate

[PeterGwee]

Cocopeat? For what? Flourite is enough. It is a very good substrate itself.

Regards
Peter Gwee

[dts_spawn]

do i need to put fert stick after sometime? and if the tank is too big for 1 bag of the fluorite, can i use cocopeat+flourite?

[Plantbrain]

It might help to understand what different fert's are used for and substrate's role.

You don't need anything in the substrate to grow nice plants. You can dose everything to the water column.

I did this for about 10 years.
I used sand and Reverse Flow UG filters.
Worked great.

So base ferts are not needed.

Substrate enrichment is needed if..............you decide to limit something in the water column, say Fe, Mn, PO4, NO3 etc.

Only when there is not enough the water column will plants remove it from the substrate.

This might be desirable since it slows plant growth down, hopefully without stunting. Balancing that can cause some issues.

OTOH, having some enrichment to the substrate is a good back up plan for the plants if you are unable for whatever reason to dose routinely to the water column or have some weird belief that a rich substrate and nutrient poor water column will somehow limit algae.

Flourite and other more costly substrates tend to have better characters for nutrient exchange, this allows a better source of Mn, Fe.

Fe and Mn are the two sub nutrients I would certainly add.

Plain sand and a bag of flourite will work, but at 40$ a bag, that's pretty expensive. Not sure it's worth that.
Here it's 15$ US, so the cost is not too bad for us.

ADA stuff is good also but also cost a lot. It's about 3x flourite here so they never made it here in this market.

Mulm is added to cycle the new substrate and adds what's missing from a new vs an established substrate

Peat is added as a longer term source of organic material and also to reduce the substrate some in the beginning stages before the bacterial colony grows in and takes over this role.

Gravel is added for physical rooted plants. Flourite etc can be added for better cycling of nutrients and also laterite can be added also.

I've never been that keen on enriched substrates with NPK in them, traces are fine and good. Some folks will add PNK to their substrate and keep the water lean and then replace the substrate once a year or two. Sounds like a PITA and I can grow all the plants as well without doing that, I would say even better.

Regards,
Tom Barr

[dts_spawn]

Thank you, Tom Barr for your very informative post!

[Plantbrain]

An adendum:
Although not keen on enriched substrates particularly, I have tried them many times. They did not help unless I limited some nutrient.
That is not to say they are not useful for particular routines, they do not hurt IMO/IME unless you add NH4/urea base stuff.

Ocassionally, vacuuming out sections of mulm and ferts might be needed as they sometimes might sour due to accumulation rates.
If you have some spots that never seem to do well with plants, try this.
I always uproot to prune, "toppers" often leave the plant roots alone and these sometimes will die back and leave all this organic material down there to rot.

Regards,
Tom Barr