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Water changes

Kitbag

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20 Mar 2018
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Coulsdon, Surrey
I have been keeping tropical tanks for 15 years and understand the need for regular water changes in those.

I’m new to planted tanks with low bio load from fish and am surprised by the size of water changes that are being carried out in this side of the hobby.

What’s the reason behind such large percentage water changes?

Thanks in advance.
 
It's really all about reducing the concentration of both dissolved and solid organic compounds to help to prevent algae.
Plants grown in high-energy tanks - those that are CO2 injected, with eutrophic dosing - produce a large amount of metabolic waste, and so require regular and substantial water changes.

Plants in low-energy tanks grow around 10x slower and therefore do not produce so much metabolic waste, therefore water changes do not need to be so substantial or frequent.

In a newly set up tank even more frequent water changes are often recommended to reduce the ammonia spikes often associated with cycling and to cope with the organics released by plants transitioning from emersed to immersed growth.

Plus water changes in general help to keep critters healthy and happy.
 
Hi all,
I have been keeping tropical tanks for 15 years and understand the need for regular water changes in those. I’m new to planted tanks with low bio load from fish and am surprised by the size of water changes that are being carried out in this side of the hobby. What’s the reason behind such large percentage water changes?
I'm a low tech tank keeper, but I still like regular water changes. I change a small volume every day, but you could change more water, more infrequently.

I've been advocate of planted tanks (with heavy planting) as a technique for maintaining water quality on non-plant based forums and people have often assumed that plants are instead of water changes, and that plant based filtration is instead of microbial based filtration, but neither is true.

Plant based filtration is always plant/microbe filtration, and plants are an adjunct to water changes, rather than an alternative.

The advantage of actively growing plants (whether you add CO2 or not) and water changes is that you can maintain very high quality water, and as @Tim Harrison says high quality water helps keep your livestock healthy.

It has come up quite a lot in the <"forum as a question">, partially because Diana Walstad, in the first edition of <"The Ecology of the Planted Aquarium">, didn't recommend water changes.

Have a look at <"Fish health....">.

cheers Darrel
 
Planted tanks get a bit lumped together sometimes. Those doing high tech aquascapes with CO2 tend to be the ones also doing 50% weekly water changes. Partly because they often use EI dosing, which is basically adding more nutrients than plants could need so they never run out, and managing that by changing 50% of the water to keep it balanced.

There is much more variation to planted tanks than just that though. People have all sort of water change schedules from big and fequent to average to very infrequent. It just depends on the tank setup, the plants and the fish and what you want for your own tank.
 
The advantage of actively growing plants (whether you add CO2 or not) and water changes is that you can maintain very high quality water
I think that trying to grow healthy aquatic plants has made an enormous contribution to critter husbandry, not least by providing better water quality. In fact it's bought about several hobby paradigm shifts, overturning accepted aquarium dogma. Most of us are aware that inorganic nutrients don't cause algae, and aged water does not have magical properties.
 
Some here are going from cichlid tanks to planted tanks and are just set up for large water changes (eg drains / drums with pumps / etc where they heat / stabilise tap water over night - mainly for deeper water African cichlids that don’t handle changes in water so well). And as mentioned above are doing a larger water change to reset the tank from ferts dosing. While shifting house, I had to let the water changes slide quite a bit and did think water quality / smell was off (high tech tank).
 
Could it be possible to run a high tech, highly dosed tank with say monthly water changes with the help of a huge activated carbon/sand stack to get rid of the organic compounds? Maybe have it purge the entire tank once a week after lights off?

I don't dislike doing water changes, it's part of the fun - but it's fun to think about.
 
The PPS fertilization method reduces the amount of water changes, but this only works if you are comfortable with water test kits. The process requires weekly water testing and monitoring to judge when to do water changes. Success comes with mature tanks only, from my experience, but in stable, moderately lit tanks with reduced dosing and CO2, water changes may only be needed every two or three months....... Now I'm going to wait for the 'booing' and 'hissing' to start from the opponents of water test kits for planted tanks......;)
 
Oh, and PPS stands for perpetual preservation system.
 
Success comes with mature tanks only, from my experience, but in stable, moderately lit tanks with reduced dosing and CO2, water changes may only be needed every two or three months.

You can grow plants in quite appalling conditions, and grow them successfully, without much algae, irregular or no water changes, as you said, as long as the tank is mature. But you can't keep fish in such tank...They won't last long. So what one's success entails is not the same as another's definition of success.
 
Hi all,
Plus IME, you can pretty much get away with a multitude of sins in a mature planted tank...they are incredibly biologically stable.
That is it, <"mature planted tanks"> give you a lot more wriggle room. If you have floating, or emergent plants, they have Diana Walstad's <"aerial advantage"> and that gives even greater resilience.

We don't know exactly why, but densely planted tanks definitely have greater stability and resilience.

As a general rule, in ecology, low nutrient loadings foster diversity, and diversity brings stability. This works over the whole range of ecosystems from <"microbial assemblages"> to tropical rain-forests.

cheers Darrel
 
But you can't keep fish in such tank...They won't last long. /QUOTE]

They do quite well. L
But you can't keep fish in such tank...They won't last long.
You clearly have missed something. I've been keeping healthy fish in all my tanks, using PPS, for years. This has nothing to do with doing 'no water changes'. Water changes are necessary when certain thresholds are crossed. It's about maintaining a balance between fish health and plant health, and there is a huge sweet spot in which both can thrive. I have had tanks to go without for about 100 days, but often if one nutrient, or TDS, or perhaps water clarity is beyond a certain threshold, then I do a water change. I do over 50% in each case.

But let's also walk a mile in my shoes: In the winter in this country the tap water temperature in near 40 dF, or 4 dC. I have a 330 gallon fresh water, heavily planted tank (lots of fish). I need to keep the water temperature above 76 dF to keep Barclaya longifolia from going dormant, and have a hot water tank that won't keep up if I try to fill the tank as quickly as the water pressure will allow. So, when refilling the tank, it needs to be done slowly, and the water temperature of the incoming water checked occasionally to ensure the temperature is steady... not to hot, nor too cold. This takes over three hours. I knew this before I set up the large tank because in the summer, I was filling all of my other tanks at the same time with the water taps on full. I found out the hard way that I couldn't do this in the fall, winter or spring and maintain the water temperature above the mid 70s dF. So, before I installed the 330 g tank I did some homework: How to do water changes a infrequently as possible, because it takes a very long time. That's when I began to explore PPS. After years of doing this, I think I've got a better than average grasp of the situation. It works, and works well if you pay attention to details. I use Seachem test kits for nitrite/nitrate and phosphate, and a TDS meter to ensure that the 'untestables' don't add to the tds beyond a certain point. The average time between water changes varies for each tank and I haven't done the math but I'm guessing that the average for all my tanks is between 30 and 60 days. Also understand that for a new set up I do frequent water changes, several times a week in some cases and certainly once a week for the first few months.
 
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We know :rolleyes:...as for testing, are you mad :wacky:, and no or optional water changes...that's just lazy :p
https://www.ukaps.org/forum/threads/perpetual-preservation-system.28966/

Yes, I got the idea from just such forums. And I consider this forum to be the best available (and in no small part to the civility that are accorded everyone - so I'm treating the first part if this post as a joke).

IME, you can pretty much get away with a multitude of sins in a mature planted tank...they are incredibly biologically stable.

And this bit is very true.
 
Yes, sorry that was an attempt at humour, though in retrospect, obviously a clumsy one. I've said before I'm not adverse to testing, but it's as well to be aware of the pitfalls of hobby grade test kits ;)
I must admit to not really being that familiar with PPS, but from what little I've read it appears not too dissimilar to EI. It might be missing the point, but EI can be fine tuned to suit individual requirements...
Now, dosing non limiting ferts can be modified and slow and progressively reduced and with good observations, able to hit what is called the critical point(90%-100% growth rate). You bump the dosing back up to the last prior amount, that is your target specific to your tank.
Then you can reduce water changes and not need to test or worry about ferts/CO2/light, you can focus on the fish and the gardening.
Another possible alternative is Darrel's Duck Weed Index https://www.ukaps.org/forum/threads/do-we-really-need-that-much-fertiliser.48499/#post-504181 that whole thread is perhaps worth a read.
 
The PPS fertilization method reduces the amount of water changes, but this only works if you are comfortable with water test kits. The process requires weekly water testing and monitoring to judge when to do water changes. Success comes with mature tanks only, from my experience, but in stable, moderately lit tanks with reduced dosing and CO2, water changes may only be needed every two or three months...

You clearly have missed something.

Your original quote implies that "in a stable, moderately lit tanks with reduced dosing and CO2, water changes may only be needed every two or three months"

So what exactly have I missed? Reading this without any other information/explanation provided implies one will be ok doing 5-6 water changes a year....

I have had tanks to go without for about 100 days, but often if one nutrient, or TDS, or perhaps water clarity is beyond a certain threshold, then I do a water change. I do over 50% in each case.

But let's also walk a mile in my shoes:

Then you go on to explain the reason why you skip water changes, etc.....

You know, I kept 7 larg-ish clown loaches in a 80l plastic bin for 2-3 months. Nothing happened, they were perfectly fine afterwards. But why not trying to keep them a couple of times a year in an 80 litre plastic bin, every year....see if they'll be fine. The same applies to water changes. If you skip water change the odd time for 2-3 months, especially in a mature stable tank, not much will happen. But make it a habbit and we'll see then...

From your explanation I understand you may be skipping water changes for 2-3 months during winter, etc...but you go back to water changes once you can or on emergency basis. I am guessing this is not without a reason, otherwise why say you do your 50% water changes when needed and also when not restricted by weather conditions, etc...So your initial advise that one can do water changes once every 2-3 months is invalid completely and makes no sense when the full context is taken into account. You can't have it both ways....Therefore be careful when advising that one can get away with one water change every 2-3 months in a stable tank as one may take that literally....Because you're not doing what you're preaching.
 
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Yes, sorry that was an attempt at humour, though in retrospect, obviously a clumsy one.

And I apologize for being so defensive.

I must admit to not really being that familiar with PPS, but from what little I've read it appears not too dissimilar to EI.

I don't mean PPS Pro or PPS Classic. But after writing that, I quickly tried to find a site that would describe the original PPS but I can't find much. This forum certainly doesn't seem to have anything which properly describes this system.

It might be missing the point, but EI can be fine tuned to suit individual requirements...

The original PPS is just as good at fine tuning for the individual tank's requirements. Nitrate and phosphate solutions are made separate and added separately to achieve the targets for each tank. I have purposefully added livestock to provide much of the nitrates, and presently I don't need to add much nitrate at all. Just small doses to maintain the targets I've determined for each tank. I use Rex Grigg's solutions of KNO3 and KH2PO4 and dose three times per week. And on alternate days I dose a micro fertilizer either Seachem Comprehensive or CSM+B to achieve an iron concentration of 0.1 ppm. At the end of each week I test for nitrates, phosphates and dissolved solids. I am presently doing six tanks and the testing takes about 15 minutes. If one parameter is straying too high - perhaps I overfed, or something died and wasn't removed - I do a water change. I also monitor the glass algae, water clarity and time since the last filter cleaning. If anything seems out of line, I do a water change. Otherwise, I calculate the uptake of the macros over the week and top up to achieve the targets I've set. I add comparatively more of the phosphate solution than nitrate but the in-tank targets are the same as EI: Nitrates at 10, 20 or 30 ppm, and phosphate in a 1:10 ratio to NO3. When I start up a new tank I start at the high end of the target ranges and work down once the tank matures. The end result is largely dependent upon the light levels, and I try to match the type of plants in any tank to the lighting. I've experimented several times with additional calcium and magnesium but I have never noticed any differences. I dose Seachem Equilibrium after each water change to achieve at least 4 dGH as our tap water here is very soft.
 
So what exactly have I missed? Reading this without any other information/explanation provided implies one will be ok doing 5-6 water changes a year....

I'm responding to your original comment:
But you can't keep fish in such tank...They won't last long

This is factually incorrect. Fish and crustaceans do well.

From your explanation I understand you may be skipping water changes for 2-3 months during winter, etc...but you go back to water changes once you can or on emergency basis.

There is rarely an emergency. Water changes using this system merely resets the water parameters so I can more easily achieve my intended targets for the macros. In the over 30 years I've been in this hobby I've had far fewer emergencies using PPS than before I started using it. But that's not to say that I wouldn't have done just as well with EI. They are very similar.

....why say you do your 50% water changes when needed and also when not restricted by weather conditions, etc...

I don't go back to doing weekly water changes in the summer. Why would I when I don't have to? And I never said I don't use PPS in the summer.

So your initial advise that one can do water changes once every 2-3 months is invalid completely and makes no sense when the full context is taken into account.

You are reading something into what I've written that I haven't actually written.

Therefore be careful when advising that one can get away with one water change every 2-3 months in a stable tank as one may take that literally....Because you're not doing what you're preaching.

I'm not preaching - this isn't a religious forum. I was merely answering a question asked by another member of this forum and the conversation spun from that. You sound threatened by this idea.
 
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