Thoughts about mixing aqua soil and something inert?

[Jonatheber]

I am switching over to aquascaping from a standard gravel bottom. I have a high-tech 46g bowfront tank (other than the substrate) - Fluval 3.0 light, CO@ etc. My tank will have live bearers (mollies, guppies, cory cats, some tetras and a kuhli loach) My water runs high pH (around 7.8) and would love to get it to 7.4 or so, but not lower, if minimal changes from soil are possible. My tank is fully cycled at this point and I do weekly (most of the time) 40% water changes so the other balances are pretty good. For good or bad, I am not particularly cost sensitive - I have dumped so much into the CO2 (Co2art regulator, new tank, good light) that a few extra dollars on the RIGHT substrate is fine.

I definitely want tank to have taller plants in the back, with a full carpet and some smaller plants in the middle and front. If I do this right, the tall plants will hopefully be able to be easy and complicated - I'm hoping to get some colorful plants ultimately and those all seem to need to have deep roots. I am also VERY worried about all of the commentary about how aqua soils in general can cause the kH and pH to drop, and my fish need at least some minerals in the water and need a pH around 7.4 or so.

I am horribly confused by the different opinions here on the forums so I am going to through my current thoughts out there. I am thinking to put in three layers. The depths below are the first number at the front of the tank, the last number at the back.

Level 1) 1"-2" of Eco-complete - I figure this can't hurt. There will be water going through that base, there will be a place for bacteria to grow. As the soil (#2 below) starts to turn to mud, that mud will be able to sink down instead of sitting and fill in the spaces in the eco-complete. Not sure the last part will work, but it seems logical. I know some people think it is pointless, but unless it will hurt I don't see a reason not to do it. If nothing else, it is cheaper than the soil I'll use next

Level 2) 1"-2" of aqua soil only - while ADA Amazonia soil is very popular, I am really concerned that the ammonia won't be controllable for a while. My priorities here are to have a good growing medium for plants that root deeply and give off nutrients to help with growth up front, but try to find a soil that won't mess up the chemistry (guppies won't like pH that is TOO low) and won't degrade quickly. I can move my fish to a quarantine tank for a bit, but they won't last all that long because the 10g isn't really suitable for 15 fish for that long. I therefore wonder if something more neutral would be better that would lower pH slightly but not give off so much ammonia. Happy to get recommendations (e.g. Landen, Composoil (although I think that supposedly breaks down quicker)

Level 3) 1"-2" MIX of ADA and something inert but not too small like Seachem Flourite (happy for recommendations of something black here too). I don't want to do a full cap or sand because I have babies in the tank and bottom feeders and don't want them impacted. I also figure that mixing something intert with the soil will help keep the top layer more porous when it starts to degrade. I really want some soil up top - some of the plants don't have deep roots, and I have gathered from what HAS been posted that the carpet will grow much better if planted in good soil than just something inert. Doing the WHOLE tank with root tabs if I used something inert to encourage the carpet and more challenging plants in the whole bottom of the 46 gallon tank will be a royal PITA so I'd rather not have to worry about it.

This is my idea. PLEASE let me know where I'm off - I'm not stubborn. I'm just trying to find a happy medium between good for plants AND safe for smallish live bearers and bottom feeders, combined with a place that will grow the significant number of plants I want to put in quickly.

 

[Caliban07]

I’d put the soil in the bottom and the eco complete on top. Having said that eco complete is pretty much expensive gravel. It’s fairly inert. The benefit in my opinion is that it has larger grains and smaller so this results in a nice course to fine gradient for planting and will keep the soil firmly out if the water column.

If you use fertilisers in conjunction with the soil, the roots will quickly seek out the soil and once they get there things will take off. I don’t think 3 layers is at all necessary as Eco complete offers two gradients of grain size effectively giving two separate layers.

You could also keep things the way they are for microbial stability purposes and less chance of algae and use root tabs and fertilisers instead. Swapping out the substrate is going to cause a part tank reset and you may end up with all the fun that comes with a new tank.

 

[Jonatheber]

I’d put the soil in the bottom and the eco complete on top. Having said that eco complete is pretty much expensive gravel. It’s fairly inert. The benefit in my opinion is that it has larger grains and smaller so this results in a nice course to fine gradient for planting and will keep the soil firmly out if the water column.

If you use fertilisers in conjunction with the soil, the roots will quickly seek out the soil and once they get there things will take off. I don’t think 3 layers is at all necessary as Eco complete offers two gradients of grain size effectively giving two separate layers.

You could also keep things the way they are for microbial stability purposes and less chance of algae and use root tabs and fertilisers instead. Swapping out the substrate is going to cause a part tank reset and you may end up with all the fun that comes with a new tank.

Ok. How about a complete change of pace. Ditch the eco-complete (I can return it). Leave a layer of the big gravel at the bottom since it has lots of bacteria already. Cover it with inches and inches of black sand (what kind????) and use root tabs. The benefit there, I think, is the stability you are talking about AND it won't wildly mess with the water chemistry and kill the fish I have in there now.

 

[Caliban07]

Ok. How about a complete change of pace. Ditch the eco-complete (I can return it). Leave a layer of the big gravel at the bottom since it has lots of bacteria already. Cover it with inches and inches of black sand (what kind????) and use root tabs. The benefit there, I think, is the stability you are talking about AND it won't wildly mess with the water chemistry and kill the fish I have in there now.

The sand wont stay on top. The larger particles will naturally work there way to the top due to granular convection or ‘the brazil nut effect’. But thats not so bad.

If I were you I’d try gravel and root tabs and dose the water column first. You have nothing to lose this way because you can always proceed to the next plan if you’re not happy with the results whereas if you change things by adding or swapping now it will be a lot more work going back or changing things again.

How large is the gravel size?