Do I dare replace my substrate?

[Hobbit]

Okay. So. My 55 gallon was originally supposed to be a Walstad setup. I got impatient when the pet store didn’t have the sand I wanted, so I capped the soil with a layer of imagitarium gravel.

Fast forward a year and a half.

The pH of my heavily planted, full-of-driftwood, barely-water-changed tank is 8.4, with 300ppm hardness and 300ppm buffer. (Max level on the aquarium coop test strips.) The water out of my tap is almost RO, it has so little in it. The black coating on the gravel is wearing off. So given that plants and driftwood are supposed to lower your pH over time, and the fact that I don’t have this problem in any of my other tanks, I’m 99.9% sure the gravel is sending my pH through the roof.

The fish are doing fine—they’ve adjusted to this over a long period of time. I think they’d be happier in a lower pH environment but they’re doing okay. But I know if I ever want to add new fish, they’ll have a rough go of it in this very very hard, alkaline water. I’d also like to be able to grow stem plants in here. At the very beginning of this tank I had beautiful stem plants! But based on the fact that they all died and I’ve never gotten them to grow again, I don’t think they can handle the high pH. (The swords are also nitrate hogs. I fertilized yesterday and today the nitrate is 0.) Plus, the gravel does a terrible job keeping the dirt where it’s supposed to be. There’s always particulates floating everywhere, which I think contributes to my small-leafed plants growing tons of algae. The mulm collects in those plants and the algae love it.

So the question is… do I dare change my substrate?

I think I’d replace everything with a fine gravel, something on the darker side that still looks natural. Forget the Walstad. I love that method, but the Walstad ship sailed for this tank long ago.

I really want to, but I have no idea how, given that this is a dirted tank. I could empty the whole thing and try to scoop the substrate out, but that seems really hard. Even if I get the tetras and gouramis out of there, I’ve got two plecos, two yo-yo loaches, and two otos that I highly doubt I could catch without tearing out the entire scape. And I know my sword plants will not be happy if I uproot them.

I could try to replace the substrate one bit at a time, vacuuming out another section each time I do a water change. I had to do that when I replaced the rock in the front right corner. It kicked up a toooon of dirt but that cleared in time. Does that make the most sense, so I don’t have to move anyone? I’d never get all the gravel out, but maybe I could remove enough that the pH goes down. I’m just imagining that between the loaches and the Malaysian trumpet snails, the old and new gravel will get mixed together and then I’ll end up throwing out a lot of new gravel every time I try the next section. That or I’m stuck sorting gravel. 😛

Help!!

Edited September 7, 2021 by Hobbit

[Keeg]

Ultimately it's your choice on what you prefer to do. When I replaced my gravel, I didn't want to wait and stress out the fish every week with changing substrate. So I changed it in one go stressing them out one time rather than many. I used sand with bacteria in it so the cycle would still be there so dont change the filter to make sure there's enough bacteria to handle new substrate assuming it doesn't come with bacteria. I pushed all the gravel to one side of the tank and then set up half of the other side where the fish could hide and stuff. 

As for the swords, I like to think of them as a special crypt. Whenever you buy one, you just have to expect it to melt all its leaves off, but eventually it will recover. 

 

[MJV Aquatics]

I'd say that you're stuck unless you totally tear it down to start over.

Edited September 7, 2021 by MJV Aquatics

[Guppysnail]

On 9/7/2021 at 2:20 PM, Keeg said:

Ultimately it's your choice on what you prefer to do. When I replaced my gravel, I didn't want to wait and stress out the fish every week with changing substrate. So I changed it in one go stressing them out one time rather than many. I used sand with bacteria in it so the cycle would still be there so dont change the filter to make sure there's enough bacteria to handle new substrate assuming it doesn't come with bacteria. I pushed all the gravel to one side of the tank and then set up half of the other side where the fish could hide and stuff. 

As for the swords, I like to think of them as a special crypt. Whenever you buy one, you just have to expect it to melt all its leaves off, but eventually it will recover. 

 

This push to the side then vacuum everything at once out is with a wide piece of hose tube from hardware store is how I alway replace substrate. I think one stress hit and done is better than repeated stress hits. Just my opinion my fish were never worse for the wear over it. 

[Tihshho]

If you have a place to home all the fish, you're best bet is a full reboot of the tank. Drain the water as low as you can go and scoop out the substrate into a trash can (unless you want it for something else) From there take the tank outside since it's still fairly nice, hose it out so you're not dealing with as much floating particles later. 

From there go to town and set it up the way you want! If stems are your goal and you want to get into high tech to support nice stem growth, now's your chance!

Do yourself the favor and get all the hardware/substrate/etc that you need now before the tear down. Go through the list of everything you finally get on hand to make sure you have everything you need. Once you have that done and some time on a nice day, go to town and clean the tank and get it ready to be the tank you want.

If you're looking into active substrates, be aware that once you start with them they are only good for a certain amount of time, they don't last forever so you will have to replace substrate every so often. There are certain ways around not making a mess that people show all the time, but IME no matter what you do, expect a mess because either your hand slips and you stir something up, your drop what you're using to scoop or the siphon you're running clogs and back feeds and stirs things up, or your cat decides to micromanage and knocks something in the tank... Been there done that with all of them. Also, when it comes to active substrates keep it in mind that they are not equal. Some have better nutrients, some have better weight to be able to plant, some look better, and some don't turn into mud. IME Brightwell has been the company of choice for me for active substrates, their color options and particle options for size mean the world in terms of getting what you want. They also seem to last the longest (around 2-3 years) depending on how much you supplement root feeders.

The kicker with going this route is I strongly recommend running RO/DI. Why? Because you can control what goes in the water better and you will be the keeper of the kH, not the powers that be that feed your tap. I know you said your tap comes out close to RO low, but you'd be surprised the fluctuations you get seasonally, as well as the vast different in clarity of water out of an RO unit. On top of that, with your various other projects it seems you have you'll have RO at your disposal... If you run into an issue later and need RO you've got it. You decide to make a nano high tech setup to give away to a friend, you have RO to start it and supply them, or you want to dip your feet into the reef world... well you're half way there. 

The world is your oyster with your new setup. Plan it out so that you don't have to go through the struggle later on, but I guess to some this struggle is part of the fun.

[Isaac M]

Hello @Hobbit! I recently changed the substrate out of my 55 gallon aquarium that had organic soil in it as well. I changed mine out just because I wanted to do something new. My 55 gallon had an average of one inch layer of soil capped with an average of one inch layer of black blasting sand. I also changed the lighting and changed the filters from a canister filter to 2 sponge filters. I would recommend the following:

Remove the fish and add them to either another aquarium or a 5 gallon bucket with your filter running on it to keep your beneficial bacteria alive. Removing the larger hardscape and draining the aquarium down will help with catching the fish. 

Then remove the plants and add them to the bucket or aquarium with the fish. Then remove the substrate and anything else remaining in the aquarium. You can either scoop it out like I did or you can try using a wet dry vac to remove the substrate (I have seen others do this but I personally have not). 

I also took an extra step here and cleaned all my glass so the aquarium looked brand new. 

Then you can begin adding in the new substrate and the hardscape/plants/filters/ other equipment etc.

I would also recommend adding in half of the old water minimum given that your tap water is vastly different than your tank water that your fish are used to. With water changes, the water chemistry will gradually change and your fish will acclimate to it as well. 

Then add the fish back in and enjoy your aquarium! 

Good luck and let us know how it goes! 

 

[Streetwise]

I have swapped sand caps for gravel caps in a few organic soil tanks for better substrate breathing. I ran extra HoBs to clear the water. It was messy, but squeezing out sponges into buckets was most of the work I did post-change.

[Hobbit]

Thanks everyone! This is what I suspected, but I needed some wise voices to convince me. An all-at-once, huge re-set seems like the way to go. You all are helping me picture what the process would look like, too.

@Streetwise if it was just the mulm dust, I’d probably leave it. I don’t mind squeezing out the sponge filter every two weeks or so. It’s great for my potted plants! 

I’m probably not going to have the time or energy to do the switch anytime soon, but I’ll start planning and collecting my supplies for the big day. I’ve got a dustpan I can use for scooping and a shop vac I might be able to use. I’ll need the gravel of course, and more buckets for saving the water… a lot more buckets… hmmm…

Right now I have a fishless 10g planted tank which would make a great hotel. I’ll probably add some stress coat. And maybe put the plecos in their own bucket because they’re bossy.

I don’t think I want to mess with active substrates this go-around. I’ve used some Fluval stratum in my smaller tanks and it wigs me out how it absorbs stuff and lowers the pH. I feel like I never know what’s actually in there.

Oh! This could be my chance to replace the powerhead with my new co-op one! 😃