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Discussion Starter · #1 ·
Care to discuss the pros and cons of deep, i.e. 4"+ (10cm+) substrates? These two local fish shops talked about it on YouTube, that they have extra deep, 4" -8" (10cm - 20cm) of substrate in their tanks, and never bother with them for years if not over a decade. Those tanks were all heavily planted with slow water movements and small fishes; owners just top off and seldom or never change water.

Any opinions on this approach?

 

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Seems like it could be dependent on the type of substrate used. I have had up to two inches of "dirt" capped with two inches of pool filter sand with no problems and 20% weekly water changes. I have since re-scaped with 8"+ of Fluval Stratum and still see no issues. I dont have much experience on the matter, but it seems like a coarse substrate would be ideal for deeper scapes to keep things from going anaerobic.

This is all based on my limited experience and use of logic. I am interested in what others have experienced.
 

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Discussion Starter · #3 ·
Seems like it could be dependent on the type of substrate used. I have had up to two inches of "dirt" capped with two inches of pool filter sand with no problems and 20% weekly water changes. I have since re-scaped with 8"+ of Fluval Stratum and still see no issues. I dont have much experience on the matter, but it seems like a coarse substrate would be ideal for deeper scapes to keep things from going anaerobic.

This is all based on my limited experience and use of logic. I am interested in what others have experienced.
Some hobbyists enjoy changing water, I am not one, these two videos were from fish shops sharing their no water change tanks. I was intrigued.
 

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Some hobbyists enjoy changing water, I am not one, these two videos were from fish shops sharing their no water change tanks. I was intrigued.
I am definitely interested in a no water change system, I just have yet to arrive at that point. May there be a correlation between deep substrates and sucess in no water change systems? I am following this thread!
 

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Every tank is different. Same for the experience level of hobbyists. Since most come and go after just a year or two and hit a plateau of what they're willing to learn, weekly or bi-weekly changes are generally what everyone does. But there are some who only change water once every couple months. Those are usually heavily planted, sparsely stocked setups that don't require a lot of effort.

All of my tanks are extremely low maintenance and I keep regular tabs on them. And in nearly every system, there's always some sort of nutrient depletion if regular water changes aren't taking place every couple weeks. That's usually the case in most planted tanks - even trivially. For those who don't top-off with RO/DI water, nutrient build-up (dissolved solids) can become a huge problem over time. Experienced hobbyists usually don't have much issue tweaking their water chemistry, so some things can be more manageable.

Most of us strive for balance and stability and water changes help make those things possible. Water supplies are generally flushed and replenished in nature, as well, so that's another reason to conduct regular changes.

My Halocaridina rubra tanks only get changes once or twice a year but they're a different beast entirely.

Edit: whoops, hit post too quickly. Here's the rest.

Deep substrates are also one of those things that tend to be easier for more experienced hobbyists. They're 100% not the secret to anything. Some can provide more surface area for nitrifying bacteria if they don't get super-compacted over time and there's decent flow. But I've never had a tank with a ton of substrate be easier to maintain than one with a more rational/normal/usual amount. Doesn't matter if it's something like an ADA product or pool filter sand. Maybe less fertilization necessary for nutrient-rich substrates in the beginning but eventually they all get depleted. In practice, I've never had a tank with just an inch or so of substrate be easier to maintain than one with more.

Personally, I tend to look at people who advocate these no water change tanks (or use this filter system because it's magic, keep deep substrates because they're the secret) as charlatans setting newcomers up for failure. When it's really not complicated to do a weekly or bi-weekly change in most instances. It's also a nice time to give your tank a look, test parameters if necessary, and enjoy the fruits of your labor.

I think if people really don't want to (or can't because they're differently abled) put in the effort to physically maintain their tank, they should consider an auto-change system. They're usually not that complex and don't have to be crazy expensive.

I like the middle ground. I don't physically have to do much to change water beyond flipping a switch when I'm at the tank. Look through everything, start a siphon to remove water and any detritus that's unsightly, trim anything necessary, inspect lighting and other equipment, peek around the filter, squeeze out sponges occasionally. Then flip a switch to turn on the pump I keep in a reservoir for refilling. I even do something similar when I have tanks that require carrying a bucket - just keep a small pump with tubing attached in the bucket to make refilling easy. And by carry, I mean I have a little wheelie cart from Harbor Freight that I move buckets or Brute cans on so I put in even less effort.
 

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Thanks for posting. I also am intrigued by Justin at Ocean Aquariums in SF, and am in the same boat as OP in this post. I have a 55gal I want to plant. I am going for substrate depth variations between 6"-8" throughout the tank. I am open to changing out water but no more than 10 gals a week and add a little fresh every day. I have great access to every type of sand gravel and clay on my property where I live thanks to me being on a river and a creek and the fact that I sit on an alluvial fan and since I live so far away from stores etc my goal is to utilize my classifiers and build with what I have here. Thanks for the feedback on this subject everyone, back to reading the rest of the forum now.
 

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This is a side view of my 75 gallon tank. That substrate is 10+ inches deep of sand. Some lava rock mixed in but mostly sand.



I did this for aesthetic reasons. I wanted the back built up for a bunch of rock. I do 70+% water change every week and use an auto doser with pps-pro method for ferts.

If your aesthetic design calls for a deep bed of substrate then go for it. If it doesn't then there's no reason to do it and certainly a bit cheaper not to bother. The 'secret' to exporting nitrates is to put in some plants. Just my 2 cents.
 

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This is a side view of my 75 gallon tank. That substrate is 10+ inches deep of sand. Some lava rock mixed in but mostly sand.



I did this for aesthetic reasons. I wanted the back built up for a bunch of rock. I do 70+% water change every week and use an auto doser with pps-pro method for ferts.

If your aesthetic design calls for a deep bed of substrate then go for it. If it doesn't then there's no reason to do it and certainly a bit cheaper not to bother. The 'secret' to exporting nitrates is to put in some plants. Just my 2 cents.
That looks great, I personally really like the way a deep substrate looks, and yours looks fantastic.
Do you do 70% weekly because the fish are finicky? Would you potentially do a lesser water change if you were holding mostly plants? For example with my tank, I have 32 strains of plants on their way in the mail and the tanks main purpose will be to grow the plants and eventually turn it into a shrimp colony with a couple siamese algae eaters for cleanup help.
 

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That looks great, I personally really like the way a deep substrate looks, and yours looks fantastic.
Do you do 70% weekly because the fish are finicky? Would you potentially do a lesser water change if you were holding mostly plants? For example with my tank, I have 32 strains of plants on their way in the mail and the tanks main purpose will be to grow the plants and eventually turn it into a shrimp colony with a couple siamese algae eaters for cleanup help.
I do 70% because I am dosing fertilizer which gives dozens of different compounds into the water to keep my plants happy and I have absolutely no idea how often those various compounds are being consumed by plants. I mean other then nitrate, I don't even have tests for the things I regularly put into my tank. The one thing I do know is excess of nutrients can cause algae and I rather not have to deal with a bloom because I have too much zinc or some such. Anyway the best sucess I have had is when I am doing big water changes so that's what I keep doing.
 

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Discussion Starter · #10 ·
May be one day I shall do an slightly controlled comparison test, with four tanks of same size probably 10g:

Tank 1 : 5" substrate, foam filter, heavily planted with Amazon swords and guppy grass, 6 platys, 6 Corydoras,
Tank 2 : 1" substrate, otherwise same as 1
Tank 4 : Same as 1, except powerhead on foam filter to have more water movement.
Tank 5 : Same as 2, except powerhead as 4.

Monitor the nitrate load daily and plant growth. Let's say the test will be for 1 year, one can see how long each tank can last before needing water changes, let's say the water change when nitrate level hit 20 or 30?
 

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I did a 4" thick eco complete substrate, because - in my experience - it helps with natural filtration. I have to sand cap some places that I want finer plants to grow, but I rarely do water changes. That being said, I also keep very small fish, and my tanks are heavily planted. I also take a very unpopular route, and use rainwater. So take my advice with a grain of salt. (or use it as a basis for your own experimentation, whatever you like)

FYI - I like to set up test tanks, with locally captured specimens, to see how well my ideas are going to pan out. If the local flora and fauna work out, with almost no cost, I don't have any fears about scaling up, and spending some $. Tomorrow, I'm going out to collect sail fin mollies, least killifish, American flagfish, and freshwater shrimp. That's going into a 10 gallon tank that I've lined with pine bark compost, worm castings, and that thick layer of eco complete that I spoke of. It's already been proven on a 1 gallon jar, that's been sitting on my porch, with plants, for almost a month. (and takes better water readings than my maintained indoors tanks)
 
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