air stone during the day. Opinions on whether it’ll rob the tank of CO2 seem mixed, some even suggesting it could help add ambient CO2 as I’m not injecting
I want you to have a lovely aquarium to look at with healthy fish. It is such a beautiful hobby when things 'click' together, but these are ecosystems, they vary and my personal recipe for success is not some set of rules which must be followed. But I think there are gimmicks in the hobby, expensive ones, which claim to help in having a successful planted tank, for example: electrolysis for green algae control, fancy alternatives media to foam in filters, lights with spectrum gaps to reduce algae, 'liquid carbon', etc., etc., but some things in my experience work, CO2 injection, not using an air pump driven air stone, using a UV light in a filter for disease control and using a decent intensity of broad spectrum light to give the plants the energy they need for photosynthesis.
It is very important to clearly understand that there are lots of very good reasons for using an air stone.
This is particularly so with larger bodied fish, my gold fish pond requires oxygenation at night in the summer, but pumping air into a tank does not raise CO2 levels, despite what some say on some forums, those more scientific than me will no doubt explain. Despite there being over 400 ppm of CO2 in air, it does not dissolve from the bubbles into the water. Aeration definitely leads to gassing off of what little CO2 there is, however, some plants can cope, floating plants have the aerial advantage and some that deploy biogenic decalcification.
If you turn an air stone off, wait 24 hours and measure pH then turn it on again and measure pH after around 8 hours, the difference is very striking.
The four biggest early lessons I learnt in hard water London for successfully growing plants whilst keeping small fish, were, I think, some may not agree with me:
1. Turn off an air stone at least during the photo period but of course beware of hot weather and the implications for BOD and think of the needs of heavier bodied fish. I don't use air stones normally at all, but in hot summers I should, and will, in the future. 2022 I had a few fish losses during the heat wave, mainly rosy barbs, cooler water fish, with heavy bodies, they just couldn't cope. The small tetras were fine as were the corydoras catfish.
2. Make sure the light is strong enough for photosynthesis - that normally meant, back in the 1980s - a sort of plant growing 'dark age' - adding an extra cheap domestic fluorescent tube or two, additional to the tank to the inadequate but expensive so-called plant specialist tube provided. Many tanks today, are in contrast, adequately lit by one LED bar, but generally, success requires either a single high lumen bar or two. I have used four on my main tank, roughly 1 watt of LED per litre, but currently it is lit by bog standard floodlights, again roughly 1 watt of LED per litre. Many think that way too much light, all I can say is that yes it is too much for shade loving plants and yes I inject CO2. But with much less I don't get good growth from Rotala macrandra. I have used a lot less light and grown crypts, slowly but healthily, with around 1 watt of LED light per gallon.
3. Make sure the substrate is of an appropriate particle size - pea gravel alone is too big, it can be used to top more suitable substrate, silver sand, clay, garden soil, horticultural grit, pond soil, compost and even, expensive pelleted aquarium soil, though the latter turns into mush within a year or two in my tanks so I do not use it. I advocate that soil is put in a mesh bag to reduce mess, but I sometimes don't bother myself and come to regret it. My small tank was a murky mess last week after I pulled out more than 50% of the plants, better now but not completely clear.
4. Just as with alkaline soil, with alkaline water sequestered Iron needs to be added, I still do this, some 40+ years on when I change water, when using soft water in Belfast in my childhood and youth I never added Iron and never needed to. Hard water grows plants but iron deficiency with hard water is common.
There is a lot a debate about under gravels, I have never been successful with plants and under gravel plates but I am led to believe by many here that hard water not the movement of water through roots, is probably the reason. If, I could grow plants with under gravels, I would, they are perfectly matched to the size of the tank, hidden, easy maintenance and dirt cheap to buy.
Nothing I write here is grounded in proper scientific experiment, and I honestly don't understand a lot of the science talked about in the hobby, I am not a trained scientist. My tanks are not classic show stoppers but better than 90% of tanks on display in aquarium shops and are full of fast growing plants and my fish are healthy, but as I confessed, I have had things go wrong, CO2 injection is definitely not for everybody.
A surface picture of my little tank before I attacked it. I'll post a picture of my little tank when I have replanted all the currently floating crypts. Two LED tubes and 24 hour low bubble inected CO2, the substrate is largely heavy pond soil under sand and horticultural grit.
The emerged leaves of the Indian fern have been dried out/burnt a bit and some of the salvinia is showing nutrient deficiency, the frogbit is I think fairly healthy, no water column fertiliser other than Iron had been added for months.
I wish you success with your renovation project but I too think it is important to have a good plant mass to start with otherwise algae will fill the niche. I also think Nitrates do need to be kept in check, best in the 10-40 ppm range in my experience.
