Furry_Pleco777

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Dec 13, 2021
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Wondering how to prep up lake clay to use in a tank in a way it would kill “bugs” in it?

I am about to start a large low tech tank and am gathering ingredients for substrate. Planning on a mix of things topped with a mix of newish/oldish Fluval stratum from tanks that are getting emptied to go into this one.

Since I have a lot of water all around me, I spend a lot of time looking at local aquatic flora. Almost with no exception, healthiest plants around here grow in clay of varying firmness. From soup-like, where when pulled up one feels no resistance from the roots, to heavily compacted, hard clay, which I need attack with a metal planter spoon to uproot a plant. And at times, it is a short battle.

Since some of the species in the tank are going to be local, I want to add at least 25% of their localities’ clay to the root mix. But since there will be fish in that tank, I’d like to know, if anyone had experimented with clay/mud as substrate in their tanks? Most importantly: what is the best way to disinfect it, to kill undesirable organisms in it? I am thinking about heating it in the oven for some time, but via experiment ahead of time finding a temperature, where it will not bake it solid.

Freezing may not be great, as I am afraid something might survive, plus I have no room in the freezer.

Any suggestions / ideas, hopefully based on personal experiences will be much appreciated. Cheers.
 

Allwissend

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It really depends how much you want to kill. Keeping the clay at 60-80C for 30 min with a lot of water available at all times will get rid of a lot but not completely sterilize things (spores etc). Try a small batch and see how your material acts after cooling.

I would however question the need to introduce clay as your substrate. Likely, having a clay layer near the surface (and sufficient precipitation) is the reason why you have a lot of water around you. The clay will slow down /prevent the water from seeping in the soil.

In nature, plants grow where they can.They can't afford to wait for ideal conditions. It's likely that their requirement for water determined their location, rather than their preferance for a clay substrate.

From my experience the hassle any mud/clay layer creates at every uprooting is not worth it when similar growth can be achieved with good nutrition. Some tank keeping approaches are more suitable than others to such a setup.
 

Furry_Pleco777

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Dec 13, 2021
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To kill I mean to kill everything I can. Just to be safe. I have seen all sorts if things creep out if the mud around the roots, not to mention microbes I cannot see. You make a good point as per uprooting scenario. It makes perfect sense.

Since it is a very large tank, I mean to have a number of plants with robust root systems (swords). Indeed, it would be a mess. The idea was to provide the local ones with similar nutrients. I will have “pockets” around the tank separated by rock barriers (but hydrologically connected). May just do the clay at the very bottom for the locals, who do well here and don’t need to be touched once in place.
 
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Allwissend

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Then the previously mentioned approach should cover the just to be safe part. It's not sterlie but deals a blow to most bacterial populations.

One approach that helped me minimize cloudiness was to gently wiggle the plant up, then once a few cm of the roots are visible i would cut in the substrate. Swords and the like can have tank wide root systems that would be impossible to get out otherwise.
Looking forward to see your new setup :)