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Moving from 20 to 55 gallons, walstad or no?


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I'm moving from my 20 gallons long to a 55 gallons(fish in cycle) due to overstocking and was thinking of doing a walstad style, however I'm getting a bit overwhelming on the option and not sure if I'm making a mistake. 


20 gallons long

Planted tank, seasoned and cycled

Bottom subtrate:  gravel

Top subtrate: fluval stratum

Filter:Hob and sponge


These are the three option to move to 55 gallon I was thinking of doing, any suggestions is welcome.


1. Mixture of fluval stratum and cheapest top soil( wash and drain several days to remove as much ammonia and wood as possible). Cap with leftover gravel( for mums and old bacteria) then pool filter sands.

[From my research miracle grow organic potting create too much ammonia, while cheap top soil likely to have no additives] 


2. Mixture of gravel and stratum,then use dirted gel cap to slowly insert under subtrate over time.( maybe cap with sand or gravel?) 


3.No dirted tank, more gravel subtrate mix with whatever leftover of the other tank. 


I'm leaning towards the gel cap methods as that probably the safest. 

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1) Organic potting doesn't produce that much ammonia, it doesn't contain urea like regular miracle gro and it contains mostly water insoluable nitrogen. Anything that releases less ammonia probably contains less nutrients. So, you can just use less miracle gro. And since your capping with sand very little will be able to leach out anyway. As for the gravel, its a little redundant. The stratum will grow tons of bacteria, its even one of the selling points. As for the mulm, not much will reach the gravel if it is capped with sand.

2) nothing wrong with this idea.

3) nothing wrong with this either.

Personally, I would consider either a thin layer of soil topped with a thick layer of gravel of sand, or do what you did in your first tank.

I think whatever you do, it will work out.

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Hi @AquaWaifu, what kind of plants do you want to grow in the 55 gallon?

If you have only stem plants, you can probably just forego the organic soil and focus more on fertilizing the water column.

However, if you have a lot of root-feeding plants like swords, crypts, bulb plants, vals, etc. then it would be helpful to have the organic soil.

If you have just a few root-feeding plants, then you could even just plant them in small pots with organic soil in the pots, then hide the pots by covering them with the substrate. That way you only have the soil where you need it. 

For my experience with organic soil aquariums, I have only done a thin layer(one inch or less) of organic potting soil (sifted to remove a lot of the wood, clumps, etc) capped with either gravel, pool filter sand or black diamond blasting sand that is either the same thickness of the soil below or thicker. They have all done well, here are some photos of those aquariums:

40 Breeder with organic soil and Multi-R Root Fertilizer capped with pool filter sand:




55 Gallon with organic soil capped with black diamond blasting sand:


55 Gallon with organic soil capped with pool filter sand that I did for a family member:



10 Gallon with organic soil capped with gravel, used pressurized CO2 to help speed up the plant growth process:



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Thanks for the reply, those tank look really nice.

I just realize I be moving in two year less so Walstad maybe not the best style, I remember a video by Cory "NO WATER CHANGES - Tropical Fish Store Tour." ,that may be the easier way as I like to move my scape and plant occasionally. Is there a different in deep substrate of gravel vs pool filter sand? I have 60lbs of Imagitarium Black Aquarium Sand and was wondering that be good or do I need a larger gravel? or layer the bottom with pool filter sand for anoxic and gravel on top? Not sure how many inches of each if I were to do that( I know it need to be 4-5 inches).




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