and then there were two

[seangee]

Yesterday I turned out the lights on the 20G (#3) for the last time so I should probably stop updating A tale of 4 tanks. The individual threads on the tanks are probably no longer relevant as the themes no longer exist. So I'll start again.
First there is the community tank. I did not have to do a lot here except rip out all the plants and start again, recycling cuttings from itself and the other tanks. I recently got rid of the duckweed (at last!) and I have also replaced the lid. I also made some minor structural changes so I could maintain the "dark side I had in the past. I also put back the HOB which has recently been in the 20G.
Its around 180 litres and currently home to some cardinals, pencilfish (nannostomus marginatus), lambchops and an Albino BN known as her ladyship. Currently using TNC lite at about the recommended dosage to kick start the plant growth.
Here it is on day 1.

 

[Naughts]

Very colourful! I love the large shoals, much more impactful than small groups.

 

[seangee]

The nano (Flex 15) is looking rather sad - but that is still at day 0 (or -1).

Ignore the ugly mug holding the phone.
As you can see this one has quite a lot of algae. Easy to deal with so not really a problem - I may just send her ladyship across for a week's holiday. I suspect the reason is a few months ago I started taking out duckweed at every water change and forgot to turn the lights down. I have done this now. Re-planting is another easy fix - that's mostly down to neglect. I replace around 30 liters of water every week but have literally done nothing else besides rinsing the filter sponge.
But the substrate ...
That is actually black limpopo sand. I'm pretty sure the white comes from dead MTS shells collected over the last 10 years.. This is the only tank where I regularly have to go on an MTS culling spree. I assume it because the RO water in this tank gets re-mineralised and the pH is neutral. All my other tanks have been acidic. The MTS have always been in them but they are not prolific, and I guess when they die the shells disintegrate far quicker because of the acidity. Also after 10 years of no vacuuming its pretty <coff> nutrient rich. I always say I never vacuum sand (and I don't) but in the other tanks I do run a rake through it a couple of time a year and let the mechanical part of the filter deal with what comes out. I haven't done that on this tank because of the shrimp. Now I'm nervous about touching it for fear of killing the shrimp - and it really needs replacing. I actually shrimp proofed the filter inlets in the community tank last night and was all set to move everything I could find - but DUCKWEED! Getting that tank clear has been a major pain and took infinite patience - I am not going to mess it up now!!! If they did move they would be in the community forever (which is OK) as there is no way I would ever catch them to bring them back. The Red Rilis are all pretty low grade as the group has been self sustaining for around 10 years with no new genetic input, but I can't bring myself to just wipe them out for the sake of replacing the sand. And they are still fun to watch. Getting rid of the duckweed completely will be much easier in this tank because of the design.
But what to do about the substrate?

 

[seangee]

Cleaned the canister on the community today. Not due for a few months but I figured with all the planting and unplanting it would be pretty mucky. The sponge in the HOB was very mucky at todays water change, but that was expected as I use fairly dense Poret foam in there. Since it gets rinsed weekly its never going to get clogged and does a great job of "polishing" the water.
The canister was not as bad as I expected. Yes the water was black but the sponges were fairly clean. This is by design (mine), I only have coarse mesh in there as for me the filters main job is to clean out the muck and flow the water. Of course bacteria does grow in there and it is effective for bio filtration but I am always amused at the number of people who spend money on super expensive alternative media or try to cram as much media as possible into their units. I'd rather it just did its job without having to worry about reduced flow between my quarterly cleans. The same goes for the obsession with over filtration.
I did discover that the inlet tap is leaking. Fortunately I always have a bucket and towel to hand when I do this job. It leaked about a liter of water in the time it took for the clean, and most of that time was refilling the canister with RO to reduce the amount of priming. I checked the Aquaone site (its an Ocellaris 850) and the tap or seals are not even listed in the UK, by Aquaone or any other suppliers - even though the filter is still on sale. I also saw for the first time that they recommend changing the impeller and main O ring every year. Mine are at least 10 years old . Oh well if its any worse next time I'll pull the tap apart to make sure theres no crud (or MTS shells) trapped in the seal. If not it will be new filter time.
I removed my intake pre filters. They were really mucky after just 24 hours. I'll put them back if I do move the shrimp into this tank but until then I'd rather the muck ends up in the filters than staying in the tank.
Since I have spare smartplugs from the decommissioned tanks I now have everything attached to this tank controlled from my phone so I never have to dive into the cabinet to turn things off.

 

[seangee]

That is actually black limpopo sand. I'm pretty sure the white comes from dead MTS shells collected over the last 10 years

Nope that was wrong. Today I carefully cleared out the crypts from the corner and removed most of the loose pebbles which don't add to the tank in any way. Since the crypts are well established the root network is quite extensive and I couldn't do it without some disturbance. Good news is the sand beneath the surface is healthy and black. Shrimps are also fine . My current theory is that the white stuff is just sediment from the mineralising salts. So the new plan is to lightly vacuum a small section every day followed by a large W/C. The shrimps and crypts are already used to large weekly changes so this should not affect them. Then I'll replant in the newly cleaned areas. Like the other tank I will follow a less is more approach in terms of plant density. Frogbit will come once the duckweed has gone completely. Then I'll probably add some caradina in a few months time. Haven't decided yet if the embers will stay in here or if I'll move them to the community and keep this one as shrimp only.