mixin' up a substrate of clay, peat, laterite:opinions sought..

[judy]

So the planted tank is maybe thirty to forty percent sand and the rest coarse gravel with lotsa plants, but its old gravel, with whatever peat's underneath disintegrated and/or largely depleted, set up numerous years ago before you could even find stuff like fluorite in backwater Winnipeg, Manitoba, Canada. That gravel's been kept pretty much mulm-free as I'm a bear about substrate cleaning. Which maybe the plants didn't like, but which I think the fish appreciate.
Now I wish to replenish that substrate, in a way as non-messy and un-disturbing to the discus as possible. I have a few amazon swords that need lots of iron. I add a liquid capful daily and they like that but they could use more, and the laterite balls I used to buy to stick into the gravel beside them are no longer available here, and the crushed laterite's just gonna dust up the water column something fierce, no matter how I rinse it. And I would like to introduce some clay, which has a nice high CEC. And some more peat would be good, too, I think.
Well, sez I, that's all just a huge mess in the making. So what I'm doing: I'm taking some water (treated with a wee bit of Prime of course), some clay, some crushed laterite, and some peat pellets which I'm gonna smush up even more after they soften up in the goop. And I'm gonna shape them into fairly thin bars (maybe an inch thick or less) and bake them in the oven at 200 or 225 degrees until they firm up nice and solid. Sort iron-rich, not-very-dense, high-organic-content adobe, I guess.
And I'm gonna carefully remove (by siphoning up) some of the coarser gravel the plants are sitting in,trying to keep their rooted areas relatively undisturbed and leaving some of the coarser gravel there as bio-active material, slide those bars underneath, then sprinkle a mixture of very fine gravel and coarse sand over top, and I will have a bottom layer of clay/peat/laterite, a thin middle of coarser gravel where the plants' roots are already established, and a top that will be more aesthetic and easier to keep free of detritus. I know the coarser gravel will sift up to the top eventually, but the theory is that the plants will eagerly root down into the clay/peat combo and I can slowly get rid of the coarsest gravel, bit by bit, as I vacuum routinely.
Does this make sense? Am I messing with anaerobic bacteria in a bad way by doing this, or am I mixing up a good combination? Would an inch be about right, or should it be thinner? I'm thinking the coarse gravel (which is almost four inches thick in spots and I just know that's not good) will eventually be gone, so the whole substrate, top layer included, would be less than three inches. That would, I hope, encourage the plants to root out more horizontally, which would get the whole clay/gravel biobed working more effectively.
I think.
Am I in the ballpark with this reasoning? I just haven't run across anyone else doing it this way... and maybe that's because its a STUPID plan...

[pcsb23]

Judy, interesting solution or plan. Never tried anything like this myself, but logically it may well work. I would probably make my dobie sticks thnner, and also make sure they are soft so don't bake them for too long

The thicknedd of your gravel/substrate mix shouldn't be a problem if you have strong growth from the plantsa s the roots will keep anaerobic nasties away ime. Having said that there is no reason not to thin so that may be safer.

Another option that may be worth considering is to get some seachem flourite. Another mineral rich substrate like a very coarse gravel, wash well and gently work into the existing substrate.

Be interetsing to see how it works out, good luck.

[judy]

Yeah, i'm thinking to bake them at very low temps just long enough so they're solid enough to work with-- just drying them out thoroughly, really-- so they won't start "dissolving the second I slip them into the water. The theory is that, once seated and covered with the gravel, the thin "bricks' will re-soften into the clay/peat/aterite mixture all by themselves, because they will, of course, be submerged. If this works, I may just patent it!
I didn't want to go the flourite route because I have heard so many say no matter how they rinse, they get cloudy water... but I may do that at some point, too...
Meanwhile, the husband is hsaking his head and noting he thought I was well past the mud pie phase...

[pcsb23]

hey, nothing wrong with a good mud pie fight