Possible parasite infestation... Best way to clean planted substrate?

[Luananeko]

I've been having issues with my 75 gallon heavily planted tank and the current theory is a persistent parasite infestation... I've done treatments with Prazipro, but I've been told that I need to thoroughly vacuum the gravel after or the fish can get reinfected when scavenging through the substrate. I have too much substrate to begin with (around 5-6" of gravel, a layer of eco-complete, and topped with a thin gravel layer) and want to swap out the gravel for sand, while keeping the eco-complete layer.

What's the best way to do this? My current plan is...
1) Put fish and plants all into buckets with existing tank water.
2) Drain tank down as low as siphon allows.
3) Carefully scoop out top layer of eco-complete and gravel and save in another bucket of tank water.
4) Scoop out rest of gravel in strainer to allow to dry out and store.
5) Pick out as much gravel as possible from eco-complete bucket and vacuum eco-complete thoroughly, and add back into tank.
6) Top off with dune sand.
7) Fill tank halfway with water.
8) Replant the plants.
9) Sterilize and replace decor.
10) Fill tank rest of the way.
11) Acclimate fish to new tank water then add back to tank.

Are there any steps I'm missing? Is this too drastic of a change for the fish to adjust to? I'm trying to minimize all chances of the parasite making it through the process, but I don't want to kill off my fish in the process...

Any suggestions are appreciated!

Edit: Some additional info... I have both a canister filter and a HOB filter packed with bio media... The tank is understocked atm due to having lost about half my fish over the last few months to this supposed parasite problem. I do 50% water changes weekly and use purigen in my filter as well, so in theory this should be enough filtration to prevent a mini-cycle, right?

 

[Delapool]

Following......

 

[BBradbury]

Your Tank

Hello Luan...

Seems like a lot of work. Parasites have a short life span. If you raise the water temperature 10 degrees, this will shorten it. Large water changes of half the tank's volume every few days will help. If you add a couple of teaspoons of standard aquarium salt to every 5 gallons of pure, treated tap water, it will retard the growth of the parasite.

Heat, salt and maintaining pure water conditions for a few weeks is simple and effective.

B

 

[Delapool]

Must admit I was thinking this. And then if you miss one!

Could the fish just stay in tubs for a few days and raise temp right up?

 

[jetajockey]

I have to ask what parasite do you think you are dealing with, and what led you to that conclusion? Completely sterilizing the tank seems like a ton of work. And adding salt does not necessarily mean it's going to kill said parasite, depending on what it might be. But it does have a good likelihood to stunt or kill some of your plants depending on what you have in there.

Also, what is dune sand exactly?

 

[Luananeko]

Well, the 5 days of treatment finished yesterday and I went through my planned steps to swap the substrate out since I only had a half day of work Friday (gotta love summer hours). It WAS a lot of work, took 6 hours in total to do (have you ever tried taking out only the bottom layer of your substrate, while still trying to make sure you're not throwing out any of your assassin snail army?). I've been wanting to swap to sand anyways because of how hard it is to keep the gravel clean, so the possible parasite infection was just the final straw to kick me into doing it. This also gave me the chance to give my plants an Excel bath to try and kill off the algae issues I've been fighting. As an added bonus, I realized my MASSIVE amazon sword was actually a mother plant with two babies that had grown up and into it, so it gave me a chance to pull the 2 babies out from it and reduce the footprint it was taking up

The tank already runs at 82-84F, so raising the temp 10 degrees would likely kill my fish as well as any parasites. Keeping the fish in tubs while treating the tank wasn't really an option due to the limited space I have here, plus the fact that I don't have any tubs large enough to keep them in for longer than a few hours, nor enough equipment if I split them into multiple tubs.

The theory that I'm dealing with a parasite of some sort came when talking to one of the really knowledgeable workers at my LFS. I brought in a water sample to have them double check that my own test kit readings, and everything looked perfect outside of high phosphates. 7.4 pH, 0 ammonia, 0 nitrites, 5 nitrates. Considering the number of fish I was down to (I've lost almost 2/3rds my stock) and the fact that none of them show any external signs before they die (swimming/looking normally one day, stop eating but still swimming fine next, lethargic but still no fungus/damage/redness next, then vanish or show up dead), the only thing we could think of was some sort of parasite.

I used both Lifeguard and Prazipro for treatment the last 5 days, so whatever it was, in THEORY it should be nuked... Either way, at the very least the tank looks MUCH nicer now with sand and the new layout, my loaches LOVE the sand, and my substrate is now the proper depth instead of being 6+" deep. So if my plants are a little stunted for a little while as they adjust, I still think it was worth it. I've got a mixture of amazon sword, hygro difformis, ludwiga, sunset hygro, limnophila aromatica, rotala indica, cambomba, red tiger lotus, and valisneria (didn't dunk these in the excel since they're sensitive to it) for plants.

Oh, and dune sand is exactly as the name implies... Sand taken from sand dunes near beaches We have a local supplier that collects it from Florence, Oregon, sterilizes it, and supplies it to my LFS. Inexpensive and super super soft. I put root tabs all through it, plus made sure to root my plants past it and into the eco complete layer, so there should be plenty of nutrients in there for them to eat up while the substrate bacteria and such re-establishes itself.

 

[Luananeko]

Update:
Plants seem to be fine after the substrate swap and excel bath, and fish seem much more perky and happy than I've seen them in the past month! So far everything's looking promising, but I'm waiting a few weeks to make sure there are no more mysterious deaths before calling it a success and looking to restock. Here's the new tank scape:

 

[Delapool]

Nice! How high did substrate end up in the end?

 

[Luananeko]

It's 3-4 inches deep, with the deeper sections being toward the back. I tried to pile the majority of the eco-complete/gravel mix toward the back with a thinner sandy layer, with the reverse in the front. I figure this gives my plants the best nutrients in back while leaving extra sand in the front for my loaches to dig. I don't use ground cover foreground plants due to the aforementioned loaches constantly digging, hence why I wasn't worried about keeping much of the eco-complete up there.

 

[anteatergoanna]

Wow, nice job! Looks lovely, no wonder you're fish are perky.