On the 'No Water Change," Tank

[Frogmouth Catfish]

Inspired by the recent fish room tour video Cory posted, I've been thinking about the idea of the 'no water change,' tank, and how feasible it would be for my main, heavily planted display. The interesting thing is that my nitrates are consistently consumed by plants--the real reason I tend to do water changes (once every 3 weeks to a month) is because my pH starts to drop pretty precipitously--from 7.0 down to 6 and lower the longer I let it go. I dose Easy-Green and root tabs on the regular, so I have guessed that the pH drop is possibly due to the digestive action taking place by all the fish/plants, as well as the loss of dissolved minerals and solids over time as aformentioned plants/animals use those up. I suspect I could do a 'no water change,' approach to this tank if I could solve this particular issue. Any ideas I could experiment with?

[Terry Ellacott]

I've got  soft water coming out of the tap and use it in tanks with inert substrate or no substrate. The pH of my water would drop below 5 if left alone. I used to use the sodium bicarbonate used in cooking to adjust the pH back up. I now just add a small amount of crushed eggshell to each tank and my pH is  steady around 7

[DaveSamsell]

@Cory's comments on the "no water change" aquarium & seasoned tank time (STT) caught my interest, because it was recently something that I was thinking about as well.

One of my aquariums is leaning in that direction, since it is well established, has a fairly thick substrate and is heavily planted.

Noticed the nitrates have been decreasing with every weekly water test.  Usually, the nitrates always rose slowly, in the past.

Typically change water about every 30 days or so, but am going to experiment and see if the time interval can be stretched further.  

The tank is moderately to heavily stocked and will keep an eye on overall test parameters.  

[Bill]

Diana Walstad goes 6 months without water changes and doesn't use any "artificial" fertilizer not produced by the fish, so I guess 6 months would be a good goal! 

[Streetwise]

I have setup all my tanks with organic soil and tons of plants, and I mostly just top off for evaporation. I’m willing to put in whatever it takes to be lazy! I love having stable ecosystems to do the work for me.

[FriendlyLoach]

I guess you could top off with hard and alkaline water. I just a few days ago realized that I have not done a water change on my 10 gallon planted betta tank since Covid began... And everything is fine. 

[RovingGinger]

I dislike doing water changes, out of all aquarium maintenance. My tap/well water comes out with nitrates in it, so it hardly seems worth it to change the water from 40 PPM to 30 PPM with a 50% water change. People say their fish are happier after a water change but my fish seem decidedly unhappy with a giant siphon popping into their life. 

You see so much consensus on changing water weekly, 2x/mo, regularly, whatever, and stressing that some fish "need regular water changes". To me it seems like regularly changing water is similar to watering your plants on a schedule. Humans like schedules, nature really has quite a few more variables going on in it and you're going to kill your plants if you're not putting a finger down in the soil to see if it's soaked or not before pouring more on. People don't want that answer though, they want "give it an ice cube every week". 

[DaveSamsell]

@RovingGinger, your 20 ppm nitrate water source is fairly high.  Think the highest I have seen locally, was about 40 ppm nitrate.  Fortunately, our home well water is at a consistent 5 ppm nitrate level.  📊

I know what you mean regarding unnecessarily stressing the fish on excessive water changes.  I really think it's unfair to the fish, personally.  😟

Does your source water nitrate level vary or is it generally the same?

[Mmiller2001]

8 hours ago, Frogmouth Catfish said:

Inspired by the recent fish room tour video Cory posted, I've been thinking about the idea of the 'no water change,' tank, and how feasible it would be for my main, heavily planted display. The interesting thing is that my nitrates are consistently consumed by plants--the real reason I tend to do water changes (once every 3 weeks to a month) is because my pH starts to drop pretty precipitously--from 7.0 down to 6 and lower the longer I let it go. I dose Easy-Green and root tabs on the regular, so I have guessed that the pH drop is possibly due to the digestive action taking place by all the fish/plants, as well as the loss of dissolved minerals and solids over time as aformentioned plants/animals use those up. I suspect I could do a 'no water change,' approach to this tank if I could solve this particular issue. Any ideas I could experiment with?

You would just need to dose something like Seachem Alkali Buffer to replace KH. That would solve the pH drop. Use Seach Equilibrium to replace any GH loss. 

[RovingGinger]

17 minutes ago, DaveSamsell said:

@RovingGinger, your 20 ppm nitrate water source is fairly high.  Think the highest I have seen locally, was about 40 ppm nitrate.  Fortunately, our home well water is at a consistent 5 ppm nitrate level.  📊

I know what you mean regarding unnecessarily stressing the fish on excessive water changes.  I really think it's unfair to the fish, personally.  😟

Does your source water nitrate level vary or is it generally the same?

Embarrassingly today was the first I finally sat down and tested it - my expectation was just “very hard” with no nitrates naturally and it was somewhere in the “pink but not very” range. I generally use tetra test strips, maybe I should also try the master test kit. I could use the workout of shaking a bottle for a solid minute. 

[DaveSamsell]

1 minute ago, RovingGinger said:

Embarrassingly today was the first I finally sat down and tested it - my expectation was just “very hard” with no nitrates naturally and it was somewhere in the “pink but not very” range. I generally use tetra test strips, maybe I should also try the master test kit. I could use the workout of shaking a bottle for a solid minute. 

@RovingGinger The Tetra strips work very well, IMO.

I do prefer the API liquid kits though, but it's a matter of personal preference.  

Water is truly amazing & I never understood some of it's complexities; only after entering into the aquarium hobby, has it helped my overall understanding.

[Frogmouth Catfish]

22 minutes ago, Mmiller2001 said:

You would just need to dose something like Seachem Alkali Buffer to replace KH. That would solve the pH drop. Use Seach Equilibrium to replace any GH loss. 

I was pondering that idea, but I'm uncertain about dosing. I'm using tapwater with around 60ppm GH and 40ppm KH for my water changes and top offs. The aquarium tends to start out at similar values, and then the KH drops to 20 or under, and the GH starts to slowly creep down towards 20. By this point (usually 1-2 weeks after a water change) the ph is down to 6.0 - 6.5. My tank is fully covered, so I only tend to top off about a gallon of water each week due to evaporation. I would love to be able to add Equilibrium/Buffer to the top off water, but I'm not sure how to begin calculating it, or if the amount I would need to add to the top-off would 'exceed' that water, as I know you're not supposed to just start adding E/B to the tank itself, as that can cause problems.

[Mmiller2001]

I'm not home to look, but each tells you the amount it would take to move x amount of degrees. I divided the amount by volume to move KH by .2 degree incriminates per 24 hours. I simply used a 250ml beaker with some RO water and mixed it well then tossed it in. If I was unsure, I used a bit less. I would check KH the next day and make any adjustments. GH should be even easier. I just don't see too much of a depletion in my tanks.

[DaveSamsell]

@Frogmouth Catfish, My aquariums kH & gH get depleted over time.  What I use is pure baking soda (sodium bicarbonate) to raise the kH & Wondershell to raise / maintain the gH.  

Note:  Both supplements are potent so care should be used when dosing.  Start with small increments.

The baking soda raises pH very quickly.

There are online kH dosing calculators for an added convenience, for the baking soda, to measure how many degrees of kH of change, per dose, etc.

The Wondershells are great too, but you have to be also careful not to add too much as well, otherwise the gH will get too high, over time.

Everything is a fine balance.

 

 

Edited September 26, 2020 by DaveSamsell

[Paul]

In my part of the world water out of the tap is soft and acidic. I don’t chase pH per se but I do add some crushed coral to my canisters/hobs just to add some minerals back in the water. Before I started this if a snail was added to any of my tanks you could actually watch it melt.

Edited September 26, 2020 by Paul