Natural Nitrate Removal -> DSB

Sounding pretty good according to what I've read as well. Except for the fish. One DP wouldn't likely be able to wipe out your inverts, but a small group of anything will spend all day eating everything in sight.

I'm doing a 5g DSB (plain wild mud/sand just over 2" at the deepest) with two DP's and it's clear I need a bigger tank. The DP's aren't happy even with all the plants. I just don't want to disturb the sand after all these weeks of getting it going. But the two DP's easily wiped out most of the worms, scuds and snails within a couple of days.

I think the daphnia and hyrda are some of the coolest parts of all this native invert madness. The tough part is filtration. And strong mechanical filtration quickly destroys all daphnia.

You could throw in a few pothos clippings in your sump with a light over them to help. I do it on all my tanks now and it's incredible how much faster they grow in the tank water than in the pots they are in. Some people use mangroves too, but they are a bit more expensive than pothos.

Quick question...Why the assassin snail? To keep everything in check?

Personally, if I were trying this I'd use less light. Low fish load, heavily planted with your lights will probably require dosing of macros. Denitrification won't be an issue imo. Regular dosing is usually best done with regular water changes. I'd also be concerned with growth rate of plants. Quick growth means regular pruning and rescaping. Moving rooted plants in a soil based tank is generally best avoided.

I agree, there's zero need and actually you will run low N anyway, so less denitrification, the better.

A high plant to fish ratio will always run lean on N as a rule.
Partly due to denitrification.

So water changes will be not required.

Plants have far far more surface area and uptake of not just N, but P, K, and most any TDS salts. So use them, not filtration and fish only methods, use the plants, they are the easiest method to keep the water clean over time.

Healthy plants= healthy fish, fairly simple concept.
You can use the water column or you can use the sediment or you can use both locations, matters not, there are good examples that are easy to do for both.

Main thing is lower light and reduced/no water changes for non CO2 methods.

Regards,
Tom Barr

Fun tank!

Your tank sounds fun! I think it will very beautiful, especially if you select the right schooling fish to complement the look of the vegetation and shrimp!

A few notes: Planaria, at least one of the three species I once acquired can and do attack shrimp, though it seems to require a high concentration of them and low continuously food supplies to induce this behavior. I observed them managing to crawl up shrimps' legs and under their exoskeleton far enough that they were impossible to shake. Then the poison continuously emit (the reason fish won't eat them except for paradise fish) causes them to twitch and jerk until they die. I think this is a rare phenomenon but sure as heck happened to at least thirty of my li'l critters. This is embarrassing, since I have recommended them in the past.

Your sand might be a bit too deep at four inches. Depending on the grains - their general size, but more importantly the range of sizes, and their geometry radically effect the rate at which dissolved substances can diffuse through it. If the sand has been meshed such that it has a fairly uniform grain size and the shape of the grains lends itself to remaining fluffy and uncompressed then the interstices between grains will be very open, even more so if the grains are big. If there's a wide range of sizes, the little ones tend to clog up the spaces between the bigger ones and it packs down tightly so diffusion is slow.

Most black sands I've seen are not meshed and the grains are fairly small so I'd consider leaving the sand as shallow as one inch or even less if you'r hoping for the soil/clay mixture to really go to work. Of course if your black sand doesn't pack tight deeper will work.

Plants are great. Plants which grow root systems are super for the soil. Blackworms will follow them down into anaerobic regions to feed, subsisting on the oxygen the plant pipes down to keep its roots alive down there. Another thing, the roots are largely carbohydrates and proteins, so they can be looked at as storehouses ready to release NH3, CO2, and H2S, as well as some mineral nutrients when they die, if they're left in place. the NH3 and H2S are no problem in a healthy substrate; tons of bugs eat that stuff. The CO2 diffuses up into the water column, where it will boost levels if the surface isn't agitated. I like to use stem plants which grown root systems that I can periodically cut them from and replant. Really any plant which will tolerate having its roots severed can be used to boost the CO2 output of the substrate.

Filtration seems excessive in view of your desire for elevated CO2 levels; I'm sure it will cause much CO2 to blow off.Your substrate and your plants are your filters, biological and chemical. The bioload of critters seems low enough to be easily handled without a powerful filter. Personally, I just use powerheads with mechanical filtration at about 3 -4x turnover, set to cause the surface to gently roil for good oxygenation without blowing off CO2. But then, a second DSB is good insurance and those worms will get pecked to death if the sand's too dense for them to stay fully buried most of the time. Just make sure not to agitate the water in order to keep the CO2 in it. No need for volcanic rock as its surface area can't begin to compare to sand

Endlers are very pretty and quite social but they don't really school. CPDs seem to run in packs but they hide a lot. I'm wondering if green neon tetras would do. They're very small, the school...but do they reproduce well? CPDs spawn prolifically if the conditions are right and Endlers, well they're endless.

I guess I'm really just seconding what's already been posted here, so let me also second the advice to go very easy on water changes; all the levels of contaminants will remain low so long as you have healthy plants with reasonable growth.

What's happening here is you're selecting a bunch of natural elements which, with your help, a little light, heat, and artificial circulation, will come together to form a stable little ecosystem. Actually, more traditional aquarium keeping methods do the same, except the point of stability tends towards slime and algae, dieing fish and dead plants without regular human intervention and massive filtration. The natural balance of the deep sand/soil techniques is one that is pleasing to us, keeps the critters and plants alive, and requires very little intervention. I like to think that we participate in the ecosystems of our tanks in a cooperative effort. OK, enough tree-hugger stuff. Have fun ! Please post pictures as it comes along.

I would forgot the single DP in the 125 & the 2 DPs in the 5g. The single OP may never find the food placed in there & may very well terrorize any other fish housed with it. With the 5g, it is better to keep a singleton.