Hypothetically...

[gilaesther]

Based on all the info I have read here about bacteria and cycling, I have come up with a question -

I understand (correct me if I'm wrong) that the amount of good bacteria in one's aquarium is directly related to the amount of ammonia produced in order to feed the bactia.

Based on this information, if one were to be overstocked, and producing more ammonia than a properly stocked (or understocked) tank, wouldn't the amount of bacteria increase proportionally to consume the ammonia produced by the additional fish?

THAT being the case, wouldn't the real problems with stocking have to do solely with oxygen and swimming space?

I'm not contemplating overstocking - this is just a theoretical question that popped into my head in the shower last night

I'd love to hear your opinions!

 

[andywg]

Also nitrates. The filter will normally cope with ammonia and nitrite, but the nitrates may rise too swiftly.

Many people overstock. I doubt any of my FW systems are anything under 2" per gallon, but I have massive overfiltration and do larger water changes to deal with the nitrate level.

The trickle tower sump filtration means the water has plenty of aeration (as well as having extra pumps pushing water towards the surface) so oxygen is not a major issue. Finally, the tanks with larger fish have little decoration to allow swimming room, those with many bottome dwellers are almost full of bogwood to give plenty of places to sit in.

One problem with your hypothesis would be if the filter can't handle the added bioload, hence why most people tend to overfilter.

 

[gilaesther]

Also nitrates. The filter will normally cope with ammonia and nitrite, but the nitrates may rise too swiftly.

What if you have live plants? Wouldn't they help deal with the extra nitrates?

I agree with the overfiltration idea, as well as the massive water-changes. Personally, I do 50% water changes - my fish haven't complained yet

 

[andywg]

Also nitrates. The filter will normally cope with ammonia and nitrite, but the nitrates may rise too swiftly.

What if you have live plants? Wouldn't they help deal with the extra nitrates?

I agree with the overfiltration idea, as well as the massive water-changes. Personally, I do 50% water changes - my fish haven't complained yet

Plants can help, but I don't bother with planted as to get them to grow well you generally want minimal surface movement. Minimal surface movement can place an unwanted strain on the dissolved oxygen levels. And besides, I'm a fishkeeper, my tanks have fish in them

And don't tell too many people here you do large water changes, they get all upset thinking the tank will explode or the bacteria will all die if more than 20% is changed

 

[three-fingers]

What if you have live plants? Wouldn't they help deal with the extra nitrates?

I agree with the overfiltration idea, as well as the massive water-changes. Personally, I do 50% water changes - my fish haven't complained yet

I overstock, and over filter, and my plants deal with the nitrate (generally 0-10ppm). I have and a UG filter powered by an air pump so water movement isn't that much of a problem, and even if i was...the plants would produce oxygen too, saving the day.

Over the coarse of a week, I generally do a 10% water change.

I add a rubbish liquid fertiliser, and the UG filter makes it difficult for some of the plants to grow.

I think the key is my tank gets ~2 hours of direct sunlight per day, which the plants love.

 

[Miss Wiggle]

ah come on andy, that's a little unfair!!!

everyone knows your tank only explodes at 55% changes

while yes the amount of bacteria grown is set by the amount of ammonia to an extent the limiting factor is usually how much room the bacteria has to live on, i.e. the size of the filter and space for filter media which people will often forget to take into account.

 

[andywg]

the plants would produce oxygen too, saving the day.

And what do the plants do at night? Why yes, they take in oxygen and produce CO2.

Relying on plants for adequate aeration, or hoping they can take up the strain is not the wisest of options.

ah come on andy, that's a little unfair!!!

everyone knows your tank only explodes at 55% changes

Wow, I'd best be careful my 40% changes don't go too much higher then...

 

[Miss Wiggle]

ah come on andy, that's a little unfair!!!

everyone knows your tank only explodes at 55% changes

Wow, I'd best be careful my 40% changes don't go too much higher then...

glad to be of service

 

[cuticom]

One thing I've learnt through research is by using houseplants with just the roots in the water (you can put em in a sump) reduces Ammonia, Nitrate and Nitrite in the tank. The people I've spoken to, grow fish for food and stock as densely as 6 KILOGRAMS of fish per hundred litres. Though the usual stocking is about 2-3. But even a kilo of fish per hundred litres is pretty cool. They also don't do water changes, the plants take care of it.

Just something I stumbled across. I'd say some of my tanks were rather overstocked too, but I've been using the houspelants (its called aquaponics) and it works wonderfully.

 

[gilaesther]

while yes the amount of bacteria grown is set by the amount of ammonia to an extent the limiting factor is usually how much room the bacteria has to live on, i.e. the size of the filter and space for filter media which people will often forget to take into account.

I realized after I went offline that it wasn't obvious from my original post that I had assumed an adequate breeding space fot the extra bacteria. I had assumed (and yes, I know what happens to people who assume ) the intentional addition of media on which the bacteria could flourish.

 

[Miss Wiggle]

i do love that saying!

 

[three-fingers]

And what do the plants do at night? Why yes, they take in oxygen and produce CO2.

It's not quite as simple as we tend to think .
Plants do that during the day and the night, all multicellular organisms use respiration.
People often mix up respiration and photosynthesis, and to add to the confusion there are actually three different types of photosynthesis.

Of the three types of photosynthesis, our aquarium plants use a type called C3 photosynthesis, while the other two types are used by plants that live in dry conditions because those types use less water, so luckily none of these plants are found in our aquariums .
In plants that use C3 photosynthesis, during the day they put out oxygen as a bi-product. C3 photosynthesis basically (I'm no botanist, so explaining it in detail would give me a sore head - but it is very complicated) involves bonding water and carbon dioxide to create H2CO, when you balance the equation (which I'm not going to do, I've already done my chemistry exam so I'm done for the year! ) oxygen is left over.

At night, the plants are still using the same amount of oxygen and putting out as much CO2 as they were during the day, only they aren't putting out any more oxygen or using the CO2 in the water - so your point is still valid.
However, the extent CO2 levels increase has been greatly exaggerated, and it is only a danger to fish if you are actually adding significant amounts of CO2 through use of a CO2 unit...the oxygen levels don't drop as much as you would think either, plants don't respire nearly as fast as fish.

I never said I rely on plants for aeration...tbh I rely more on my air pumps for aeration, but if both my airpump and filter stopped working I know for a fact that my plants could take the burden, and during the night there wouldn't be a problem either because there would be enough oxygen in the water from the day to carry them (and the plants) through the night.
In addition to this, you can always lengthen the time the plants get light, this means there is more oxygen in the water at the end of the day and the 'nights' are shorter so less of it is used up.
To say:

Relying on plants for adequate aeration, or hoping they can take up the strain is not the wisest of options.

just seems like a strange concept to me when we all technically rely at least partly (other contributors like phytoplankton too) on plants for 'aeration' when you think about it . If you can or cant rely on plants on for aeration depends on so many things including how 'overstocked' you are and the species of fish...some are more oxygen-hungry than others, and as consequence can deal with less CO2 regardless of how much oxygen is in the water.
Besides, don't worry, I don't actually rely on the plants for anything other than nitrate removal (and I could cope without them for that easily enough too) the plants are just an added benefit that lets me be lazy while learning more about how certain aquatic ecosystems work (yay! ) .
When keeping fish, I know complacency is not an option.
You have to regularly do water changes and/or test water stats and 'replenish' the water through additives like plant fertiliser and in very extreme cases other things like 'RO right' (although that could result in a build up of certain things), however you would really only need to add that if there was no evaporation happening in your tank so you never topped it up with water, and only after a very long period of time that depends on lots of variables.
I inadvertently do water changes when I use aquarium water to water the plants in my room then top the tank back up and I add fertiliser and regularly test the water, so that's not a problem anyway

Just something I stumbled across. I'd say some of my tanks were rather overstocked too, but I've been using the houspelants (its called aquaponics) and it works wonderfully.

Didn't that kind of filter system use to be very popular a while ago on freshwater tanks? And isn't that what they use now with mangroves on marine tanks?

I have a single Dracaena growing out of my current tank aquaponically, but I was looking to grow more variety out of my next tank, I've got a small florescent ready to be installed above that will work well for a couple of plants...I was thinking maybe a peace lilly or something, but what do you grow? And what do you use for lighting?

Floating plants are particularly useful too, though fish do eat them...and a lot of the cool ones take up too much vertical space for my tank.

 

[cuticom]

Ferns, our gardens overgrown with them so I've been yanking the smaller ones out and planting them.

Most of my tanks are already hooked up to external wet/dry filters so it's just a matter of making the first stage of the filter the plant. Get a container put a heap of holes in the bottom, fill it with gravel, stick a plant in and when you turn the filter back on make sure the water that's pumped/overflows directly from the tank goes into the planted container first. Another option is lucky bamboo though it's pretty expensive. But a single fern has kept my goldfish tank entirely free of nitrates, nitrites and ammonia for the past month. This was an overstocked goldy tank too, 50g two 8 inch goldies, 2 3 inch goldes, a 2 inch goldie, 2 one inch goldies and a 2.5 inch goldy. Its now back down to 3 goldfish and the poor plant is looking rather the worse for ewar since it's not getting enough nutrients.

I don't bother with lighting, I just use plants that prefer shade and dont need any direct sunlight

 

[andywg]

At night, the plants are still using the same amount of oxygen and putting out as much CO2 as they were during the day, only they aren't putting out any more oxygen or using the CO2 in the water - so your point is still valid.

You went through all that to tell me I am basically right...

However, the extent CO2 levels increase has been greatly exaggerated, and it is only a danger to fish if you are actually adding significant amounts of CO2 through use of a CO2 unit...the oxygen levels don't drop as much as you would think either, plants don't respire nearly as fast as fish.

My understanding is that the dissolved levels of CO2 and O2 are pretty much independent and adding CO2 is not going to have a major impact on the the O2 levels. However, you have agreed above that relying on plants to take up the slack of O2 can be bad as they cease to be putting out as much O2 in the night, thus causing a drop in O2 levels compared to the day. I have never worried about the CO2 levels becoming a problem for fish, rather that the O2 levels might get too low.

Didn't that kind of filter system use to be very popular a while ago on freshwater tanks? And isn't that what they use now with mangroves on marine tanks?

With the better cultivation of macroalgae like Caulerpa spp and Chaetomorphia spp (which are far easier to cultivate than mangroves) mangroves are falling out of fashion somewhat.

I recall seeing something Tunze make specifically to support plants and grow them with the roots in the water, though I felt they were too small to make a real difference to tanks like my larger ones.

 

[three-fingers]

Ferns, our gardens overgrown with them so I've been yanking the smaller ones out and planting them.

Most of my tanks are already hooked up to external wet/dry filters so it's just a matter of making the first stage of the filter the plant. Get a container put a heap of holes in the bottom, fill it with gravel, stick a plant in and when you turn the filter back on make sure the water that's pumped/overflows directly from the tank goes into the planted container first. Another option is lucky bamboo though it's pretty expensive. But a single fern has kept my goldfish tank entirely free of nitrates, nitrites and ammonia for the past month. This was an overstocked goldy tank too, 50g two 8 inch goldies, 2 3 inch goldes, a 2 inch goldie, 2 one inch goldies and a 2.5 inch goldy. Its now back down to 3 goldfish and the poor plant is looking rather the worse for ewar since it's not getting enough nutrients.

I don't bother with lighting, I just use plants that prefer shade and dont need any direct sunlight

Thanks, thats a good idea. I never thought of using ferns from the garden...they would be perfect! Lucky 'bamboo' is actually the Dracaena species I'm growing tight now, cost me 99p .

You went through all that to tell me I am basically right...

Kind of, you were right, but that wasn't the whole story . Many people think it is though, and this leads to many myths about plants being bad - both in aquariums, and outside the hobby in households. It's madness .
I just don't understand how the fact that plants don't produce oxygen at night leads you to the idea that:

Relying on plants for adequate aeration, or hoping they can take up the strain is not the wisest of options.

Unless your thinking of plants as being considerably more oxygen hungry than they actually are .

Because the only time that the plants aren't putting extra oxygen into the water is during the night, and there's easily enough oxygen in the water from the day to last both the fish plants the night, the plants aren't oxygen hungry at all. The oxygen doesn't gas off that fast in a tank with no surface movement, and in a tank with surface movement it doesn't matter because then your not relying on the plants for oxygen.
I feel relying solely on plants for oxygen or as a filter isn't at all unwise, it can work very well.

However, you have agreed above that relying on plants to take up the slack of O2 can be bad as they cease to be putting out as much O2 in the night, thus causing a drop in O2 levels compared to the day.

I never agreed to that . But I do agree it can be a problem in some planted tanks, such as some high-tech planted aquariums when you have extra CO2 added, which doesn't effect the oxygen but can suffocate the fish at night if not turned off since the plants aren't consuming it. And also when the lighting times don't give the plants time to give out enough oxygen (but even in high-tech tanks short lighting wouldn't always be a problem since the plants would be photosynthesise much more efficiently when the light are on - producing more extra oxygen in a shorter time).