Restocking A Slightly Acidic, Softer Water Planted Tank

10% of tank volume for substrate etc is a bit low for my tank. As I said, I previously measured that I had 170l water in a 240l tank - giving me 70l of substrate etc, compared to the 24l the 10% rule gives. I would suggest that I'm taking out about 2/3 of the substrate.

Hmm, just done the calc and that would be relatively close to the 10% rule. I have a huge block of bogwood that is staying in the tank. But I suspect it is smaller than when I last measured the water volume. (I noticed that it has some interesting knots in the wood that haven't been there before)

I was aiming for a shoal of about 25 harlequin rasboras, but made the mistake of believing the lad in the shop who said that the espeii (labelled copper rasboras)  were just a colour variant.  I want at least one large shoal, because previously my harlies behaved differently when I increased  the numbers and I love watching all the different behaviours.

PS I won't be doing weekly water changes. It is realistic to say they'll be monthly.

Even if it's a heavily planted tank? I previously had to add nitrates at water change to keep my plants happy for macro nutrients. And that can be done without the water change.

PS I won't be doing weekly water changes. It is realistic to say they'll be monthly.

Have you done this before, Helen, and succeeded in having your fish reach/live beyond their respective life expectancies? Just intrigued as to how this went for my own learning's sake. I'd be concerned about soft water not having its KH replenished - cf Sue's experience of a PH crash when she had a period of reducing the frequency of her water changes to less than once weekly - and also about what else is going on in the tank that we can't actually measure for with our home-based test kits. For example, I have very soft water, usually low nitrates (<20 although they have crept up a little lately) and plants (albeit not very skilled at keeping them) but wouldn't risk anything less than a weekly water change as I'm aware that there is much more than ammonia/nitrite/nitrates which may impact on fishes' welfare.

Hi @fcmf . I've had my fish tank (and been a member of this forum and it's predecessor) for about 8 years. My tank has been through quite a bit, including a short move from one wall in the lounge to the adjacent one. And some serious neglect due to two pregnancies.  My smallest 2 legged pet is 2 next week and I've been rejuvenating my tank since June this year. So my the latest period of neglect was over a year.

Don't get me wrong, I am NOT encouraging the sort of zero maintenance regime that my tank had for perhaps 2 years. (Look up Diane Walstead if you are interested in micro environment tanks).

But I am aware that with a young family and a job, my tank won't get the kind of attention that is encouraged. So as I sort my tank out, I'm trying to set it up so that the lack of maintenance doesn't have a detrimental effect on the inhabitants.

I was utterly amazed that my tank did so well with the lack of maintenance. Most of my harlequin rasboras and all my Cardinal tetras seemed to die of old age (I'd had them for 3 years?) . My kuhli loaches are still going strong as is my BN Plec (though I suspect Bertie might have had his growth stunted by the lack of feeding. It was concern that he might starve to death that got me sorting my tank out).

I can only put down the lack of complete failure being down to my tank being so heavily planted, with lots of bogwood and the neglect including feeding. Even now the fish don't get fed every day, so I have to be careful not to overfeed them when I do feed them.

Your plan makes a lot of sense Helen.  All the best with it.   

It would be nice to hqve regular updates on your readings as I know most of us will want to know how the tank performs with its monthly water changes. 

Weekly water changes are always recommended. I must say that I do sometimes let my tank to two weeks without a change and theres never been any noticeable impact on the plants or fish even when theres been a lot of evaporation in that period.  It's entirely feasible that for those of us fortunate enough to have low nitrate tap water the frequency can be reduced... I only have a 64 litre tank though which probably puts me a greater risk in comparison to yourself.

You should not see an increase in ammonia when adding new fish unless you add a huge number at one go. With a heavily planted tank, the plants should be able to use the extra ammonia output as soon as the fish excrete it.


Plants also help with other chemicals and biochemicals, though the amount they take up depends on the plants species. I live in Teesside where there is a lot of chemical industry, and ICI (before they were forced to sell up) pioneered the use of reed beds to clean the industrial waste water.
All animals excrete a lot of biochemicals, and there are others from the breakdown of the tank waste (fish poo, uneaten food, bits of dead plant). The plants won't be able to remove all of this, and it will build up between water changes.

It would be nice to hqve regular updates on your readings as I know most of us will want to know how the tank performs with its monthly water changes.

What a fantastic idea - it would be great to actually see this / a Walstad-type approach happening in practice - so much more meaningful and less "dry" than reading a book on it.

What sort of readings would you like to see @Matt? The ammonia is read constantly (by my Seneye) but if I get things right, it will only show variation when I add new fish.
I'm hoping to eventually balance my fish numbers and plants so that the nitrate is constant and doesn't increase or decrease between water changes.

For me, I'd love to just see the weekly ammonia, nitrate and nitrite readings, even if just as some sort of reassurance that "wow, that approach really does work in practice (as far as ammonia/nitrate/nitrite is concerned anyway) and I'm getting to live through / witness it as it occurs". While I know I could never succeed in it myself given my dire plant-keeping skills, and given that it would be typical that an adverse event would occur in my own tank if I delayed a weekly water change by a few days, it would be great to see it working in practice by someone else (who has the confidence to do so based on their previous experience), in "real time" so to speak. 

I'd love to just see the weekly ammonia, nitrate and nitrite readings

This is what I was thinking of too

@Sue would hardness be affected by less frequent water changes too?

If topping up caused the hardness to increase, would that also affect the pH? My understanding is that those minerals that increase the hardness also act as pH buffers.

Would that explain why over the neglected period, the pH of my tank increased slightly? (Less than 1 unit) And is coming down gradually with the big water changes.

I've not got my new hardness test kit yet (its in the post), but comparing my tap water and my tank water again is one of the things I need to do. My water company declares my tap water as very soft, and I'm sure it used to be only soft.

I've got quite a lot of bogwood, but that's been in the tank from the beginning. I have added some large grey pebbles. I can't remember when I added them, but it could have been just before the period of neglect. I can't see that they have eroded at all.

I did top up a couple times, though it was between 5-10 litres in total (and probably the lower end of that range). And my tap water doesn't seem to really have many minerals in it.

When I was dosing the plants, I used calcium nitrate, but haven't used that for a long time.

The pH clearly has a daily cycle, but it does gradually increase. I'm only talking about 0.05 - 0.1 unit over maybe 3 weeks and can only see it because of the accuracy of the Seneye.