Water changes for the sake of it?

[Gastroplod]

Hello all, quick query.

 

I'm not intentionally running a Walstead-style tank here, but my existing 40l aquarium always tests perfectly parameter-wise, PH stable at 7.5, KH at 6, GH at 10, Ammonia, Nitrite, Nitrate, all zero. I feed the fish once a day (mostly Hikari small granule food, and frozen brine shrimp once a week), I feed the plants once a day alternately with Leaf Zone and Florish and pull out the excess growth so they dont starve each other. If the KH drops, I buffer with a little Bicarb.

I'm super happy that it's all chugging along so well, obviously - but since the water is fine, I don't really do water changes. I was topping off with RODI when it was hot, but now that it's Australian winter time, I don't even need to do that. But should I still do a small one now and again, just for the sake of it? I don't see any reason to myself but I'm a bit like "oh.. I guess i'll just feed and not do anything" haha.

[lefty o]

change it when it needs it. imo people go way over the top with daily, and weekly water changes.

[clownbaby]

I am new to this hobby so tbh I randomly do small water changes (like literally 0.5 percent water changes). Mainly I do this just for my own comfort, because I do not want to make mistakes. Most the time this is because I need to water a houseplant or two (or twenty), so I use the aquarium water to water my plants and then do a water change while I am at it.

It wouldn't hurt, but it depends on the fish in the tank. If they're super sensitive to changes, I'd say don't do it. If they're hardy or you know they enjoy / can handle water changes, then do it if you want to! But you do not need to lol. The proof is in your tank. That being said, nothing wrong with a small water change. But nothing wrong with leaving it be!

[Yoshi]

One thing to keep in mind if you're doing frequent water changes - most dechlorinators have the affect of reducing oxygen, especially if they're over used.  I'm with @lefty o, do changes when needed.  Although if I've gone a month without needing to do one in my 5 gallon I will do maybe a 15-20% change at that point just to refresh and give me a chance to do a bit of a gravel vac.

[Tony s]

I agree with this for the most part. Depending. As long as the nitrate stays under the level you’re comfortable with. But for heavy plant loads, changing water brings in micro nutrients in the water and that helps them with growth and keeps the algae under control. 
 

If you’re waiting a month or so, be careful you don’t enter into what’s called old tank syndrome. Where your ph drops and your kh is completely used up. All of which can be tested for.

[Galabar]

Flourish will provide various micronutrients.  If they aren't all used by your plants, some may build up.  A water change can help to keep that balanced.  I'm guessing no water changes would be fine, but something might build up to an unhealthy level.  You could be just fine, until you aren't...

 

[Pepere]

Are you algae free too?

I do weekly water changes myself as I find it helps reduce algae levels significantly especially in a densely planted tank.

[gardenman]

There are reasons to do water changes besides the nitrate level. Stress hormones can build up with stressed fish leading to more stress and more issues down the road. If something's happened to stress the tank unnecessarily (chasing a fish you want to move around the tank for a half hour with a net being one example until you catch the shifty guy), a quick water change afterward can reduce the stress hormone level and keep the fish happier. (Bear in mind a water change can also stress the fish.) I had a long online chat with a chemist at one of the Chemi-Pure type companies about whether their product removed stress hormones and the outcome was, he couldn't say as they'd never tested it.

The micronutrients by and large tend to be supplied in supplements and also fish food. Most fish food has a surplus of micronutrients so the more you feed the fish the more micronutrients they'll end up pooping out. Some fish reportedly release growth inhibitors into the water and those can build up over time and stunt fish growth. So, if you're going for optimal growth, a water change can be good. If you're trying to get a reluctant pair of fish to breed, and you add some livebearers to that tank, the sex hormones released by the livebearers during conception and birth can inspire the other fish to breed. (Or so the anecdotal evidence suggests.) In that case, you obviously don't want to change the water as you want those hormones in the water. Some fish get inspired to breed after a big water change simulating a heavy rainfall, so if you're trying to breed them, a big water change is often necessary.

I watch way too many fish farms and fish breeders on YouTube and by and large, Discus breeders will do large water changes daily on their fry/young fish tanks to optimize growth. The pros tend not to waste money, so if they're doing it, it's probably a good idea if you're trying to raise optimal discus fry. Breeders of other fish tend to do fewer and smaller changes if they do any at all. And the quality of the water you're using for a water change can also be important. If it's worse than the water already in the tank, you're better off not doing a change. There is no "always do this!" answer to water changes. They can be great, or they can be disastrous. They can be vital to achieve a goal or detrimental. Just do what works for you. 

 

[doktor zhivago]

I like to change water 20-25% at least twice a month just because there's so much junk that builds up that we don't test for. 

[clownbaby]

On 5/22/2024 at 8:11 PM, Yoshi said:

One thing to keep in mind if you're doing frequent water changes - most dechlorinators have the affect of reducing oxygen, especially if they're over used.  I'm with @lefty o, do changes when needed.  Although if I've gone a month without needing to do one in my 5 gallon I will do maybe a 15-20% change at that point just to refresh and give me a chance to do a bit of a gravel vac.

I had no idea about this. Could you explain more? How and why do dechlorinators reduce oxygen? 

[Yoshi]

On 5/23/2024 at 10:12 AM, clownbaby said:

I had no idea about this. Could you explain more? How and why do dechlorinators reduce oxygen? 

https://www.aquariumcoop.com/blogs/faqs/is-dechlorinator-harmful-to-fish#:~:text=Generally speaking%2C no.,hazardous in poorly oxygenated tanks.

Cory also posted on another topic regarding water changes that I found interesting.

In the end though, I think @gardenman makes a great point.  There is no "one way" to do water changes.  The deeper I get into the hobby the more I find it's much less like math and more like art.  No one formula is going to work for everyone in all situations.  You find what works best for you and the fish you keep.

Edited May 23 by Yoshi

[jwcarlson]

I don't change water for any of the things I can measure (ammonia, nitrite, nitrate).  I change it because there's a million variables that I have absolutely no way of knowing anything about.  There are tanks that get less water changed because the fish are adult, less sensitive, etc.  But there's zero doubt in my mind that large, frequent water changes make for better, healthier fish for me.  

[s_in_houston]

No real input other than to tell you that after 5 years of fishkeeping, I can tell you there’s not any standard, accepted recommendation. And you will hear plausible-sounding “scientific” explanations behind different people’s routines. Why more changes are good for plants. Why they’re bad for plants. I’m not ready to join the “no water changes” religion (which is what this is as long as no one can point to any studies), but I also don’t care to overwork myself. I’m experimenting with water changes every other week. I know Aquarium Coop says to keep going without them until your nitrate gets really high. I know my bottle of Thrive brand fertilizer says to do them every week and they give their own rationale. Anyways. I try not to sweat it but I agree with you on the idea of doing at least some water changes since we just don’t know all the variables. Weekly 20% if you want to give yourself an amount that’s the median of all the conflicting advice you’ll hear. 

[Galabar]

If you look at it from a mathematical perspective, imagine that you are adding 1 extra unit per week of something that isn't being consumed.  With a 20% water change, that 1 unit will grow to almost 5 units.  In other words, with a 20% water change, if you are adding 1 extra of something per week, it will only reach up to 5x that amount.

With a 50% water change, that 1 unit will grow to a maximum of less than 2 units.

With no water changes, that 1 unit will just increase by one every week.

On a side note, there is diminishing returns for going to something like a 75% water change (1.33x).

Edited May 24 by Galabar

[quikv6]

While completely non-scientific, I can immediately see a noticeable activity boost in the behavior of my fish when I do a "to-the-fins" water change. In my 180, I'll do a 70-80% waterchange weekly, regardless of nitrate level. My nitrates stay at 10 or below, generally....which is the highest I want to see them in that tank. The fish (Adult Oscar, EBA, Bala Shark, and 5 Silver Dollars) immediately perk up, for lack of a better term, and start exploring and behaving differently. In my opinion, it appears to be a rejuvination of sorts, and the fish seem almost playful. This behavior lasts a few hours at the least. It is quite noticeable.

[VanDogh]

I do water change to induce some sexy time for the cory doras 🤣 

Otherwise, once a week for newer tanks and once a month or every other month for tanks that's been running for at least a year. 

[Matt B]

No two aquariums and their inhabitants are alike, they're like snowflakes! Ha Ha .  I have a 7 gal cube full of plants, gravel substrate, many cherry shrimp and snails, one Hillstream, one Endler and a lot of microfauna. Two co-op nano sponge filters,  one new and an older one with the air stone. Everything in this cube came from a 20 gal long that has been set up for over 2 years now.

I stopped doing water changes to this little tank ! (only adding water when needed)  to see what would happen. I add easy Green and small pieces of wonder shell occasionaly.  It's going on six  months now and everything is thriving!  I'm so interested to see how this does. So far so good.   I look forward to watching and monitoring the ongoing changes to this little micro environment.

[jwcarlson]

On 5/23/2024 at 7:28 PM, quikv6 said:

While completely non-scientific, I can immediately see a noticeable activity boost in the behavior of my fish when I do a "to-the-fins" water change. In my 180, I'll do a 70-80% waterchange weekly, regardless of nitrate level. My nitrates stay at 10 or below, generally....which is the highest I want to see them in that tank. The fish (Adult Oscar, EBA, Bala Shark, and 5 Silver Dollars) immediately perk up, for lack of a better term, and start exploring and behaving differently. In my opinion, it appears to be a rejuvination of sorts, and the fish seem almost playful. This behavior lasts a few hours at the least. It is quite noticeable.

Yep, most of my fish seem eager to have the water changed.  Lots of activity and while I wouldn't attribute an emotion to a fish... "happy".