Fish Tank Weed

gobbly

Well-Known Member
I'm a long time fishkeeper, from goldfish to stony coral based reef systems. I really like your setup, awesome use of natural systems :)

Some things I would keep in mind. I would not add any gardening nutrient mixes to the tank. The end product of the nitrogen cycle in your tank is nitrate, which is a readily accessible form of nitrogen that your plants will thrive on. This is the result of ammonia being broken down by bacteria, and that bacteria needs space to grow. Make sure you have lots of submerged surface area (might even look into fluidized bed filters, they are awesome, and provide more surface area per volume that pretty much anything) and good gas exchange. Gas exchange in water is directly proportional to the temperature of the water (cooler water holds more oxygen), and the amount of surface area exposed to air. Things like bubblers are great for providing movement, but actually are not a great source of surface area (they actually provide way more gas exchange by sending ripple over the surface when they break than they do rising through the water, but pumps agitating the surface are WAY more efficient). The vast majority of your surface area is at the top of the tank, and the more surface agitation you can provide, the more gas exchange will happen (up to the saturation point for that temp). The ammonia that breaks down into nitrate is provided by fish waste, so personally I would make sure you have a beefy filter and good surface area and then overstock it. Feed liberally. Fish like goldfish and mollies and the like are ideal (though goldfish like cooler water, and I'm not really sure what temp you want the water for your plants). A high stocking level will also have the added benefit of producing a lot more co2, just make sure you have good gas exchange. Frequently gravel vac the tank, decanter the detritus, and it makes very good fertilizer. There are also many micr-nut's which you can get specifically for aquarium use (many of them are must haves for reef systems, just make sure they don't have salts in them). That is what I would recommend using to dose anything that isn't already in your water. Most fish food is also very high in phosphates, just make sure you don't rinse it first.
 

smokendude420

Active Member
I'm a long time fishkeeper, from goldfish to stony coral based reef systems. I really like your setup, awesome use of natural systems :)

Some things I would keep in mind. I would not add any gardening nutrient mixes to the tank. The end product of the nitrogen cycle in your tank is nitrate, which is a readily accessible form of nitrogen that your plants will thrive on. This is the result of ammonia being broken down by bacteria, and that bacteria needs space to grow. Make sure you have lots of submerged surface area (might even look into fluidized bed filters, they are awesome, and provide more surface area per volume that pretty much anything) and good gas exchange. Gas exchange in water is directly proportional to the temperature of the water (cooler water holds more oxygen), and the amount of surface area exposed to air. Things like bubblers are great for providing movement, but actually are not a great source of surface area (they actually provide way more gas exchange by sending ripple over the surface when they break than they do rising through the water, but pumps agitating the surface are WAY more efficient). The vast majority of your surface area is at the top of the tank, and the more surface agitation you can provide, the more gas exchange will happen (up to the saturation point for that temp). The ammonia that breaks down into nitrate is provided by fish waste, so personally I would make sure you have a beefy filter and good surface area and then overstock it. Feed liberally. Fish like goldfish and mollies and the like are ideal (though goldfish like cooler water, and I'm not really sure what temp you want the water for your plants). A high stocking level will also have the added benefit of producing a lot more co2, just make sure you have good gas exchange. Frequently gravel vac the tank, decanter the detritus, and it makes very good fertilizer. There are also many micr-nut's which you can get specifically for aquarium use (many of them are must haves for reef systems, just make sure they don't have salts in them). That is what I would recommend using to dose anything that isn't already in your water. Most fish food is also very high in phosphates, just make sure you don't rinse it first.

thanks for the info...i have some rocks and a lil arch that i used t o keep in there, buthtey were getting quite nasty in less than a week, do you think i should put them back in?

also i have the drain for the grow tank trickling into the tank and it ripples the top of the surface(agitating it) i read somewhere that betas do not like water agitated...so i just have a bubler in the grow tank itself.

when i see how this turns out i may be putting together a new larger tank(i am moving soon so i will look into it when i get settled into a new home.

thank you for your intrest and info
 

gobbly

Well-Known Member
kinda interesting, because keeping fish and growing weed are both fairly specialized, and the more you learn about keeping the tank, the more I suspect your tank project will reward you with buds :)

You are correct about betas. In nature they live in mud puddles during the rainy season in asia. When the mud dries up they will bury themselves, and if it stays moist enough till the next big rain they will come back out, if not they just die. Because of this the males are incredibly aggressive toward other males. They evolved this way as a direct result of living in limited spaces. It's actually the long fins that will trigger this, and they will attack any fish with large fins. Anyway, I really wouldn't recommend them for this type of setup because you are severely limited in how many you can have. That looks like a 20-30g hex, a beta in that is incredibly understocked, and won't produce much ammonia at all (and remember, ammonia from fish waste is what provides the nitrogen after it's broken down by nitro somonas and spira bacterias in fresh water). You'll notice that in pet stores they are often in a cup or two of water, and they are quite happy in that.

For the nitrogen cycle to complete you need to grow bacteria, and that bacteria needs submerged surface area. Most people who have kept fish are most familiar with undergravel filters (I actually don't suggest using these, but they do illustrate how this all works). Basically that is a 100% biological filter, it works because it pulls water through the gravel which works as a medium for growing the bacteria you need to keep the ammonia converted to nitrate (again, think of nitrate as just nitrogen, fertilizer). You have to have plenty of surface area, be it gravel, sand in a fluidized bed, rocks etc. The more porous the medium, the more surface area, and the more bacteria it will support per volume. You also need flow which brings the water to the bacteria. You need a lot of nitrogen, and that means a lot of surface area for bacteria, and a lot of fish waste going in the water, your beta just isn't going to put in enough to support your plants growth. You could sorta fudge it by feeding so much that the uneaten food starts to rot (rotting food produces ammonia), but this is less than ideal, and will cause all sorts of other issues for you.

Another key to this is that bacteria takes time to reproduce. So when you first start adding more fish you need to do it slowly so that your bacteria is given time to adjust to the increased food source. This is incredibly important, as ammonia will start to cause harm in any concentrations over .25ppm. A good rule of thumb is to add a fish once a week (or two if you want to be really safe). Larger fish eat more, this advice is assuming you are adding 1-1.5" fish.

Far as the rocks and ornaments, they won't really hurt anything, but probably have fairly limited surface area. Not sure what you mean by them getting quite nasty... That could be normal (algae growth maybe, you will get some since you are purposefully trying to increase the amount of nitrate and that is pure plant food), it could also be a bacterial bloom (is it slimey? is the water discolored at all?). Few of those sorts of things are going to harm your fish, but they will consume nitrate and phosphates, so can limit the nutrients available to your plant.

I know it's a lot to synthesize, but if you ever have questions feel free to PM me. I can send you my email as well if you'd ever like to discuss the fish side of it more :)

And since I've already written a novel, I'll throw in more specifics about the nitrogen cycle. Ammonium (if you're not a chemist just think of this as ammonia) is the byproduct of fish waste and rotting material, and is quite toxic. Nitrosomonas, the first type of bacteria eat ammonium and excretes nitrites, which are much less toxic than ammonium, but are still not a stable form of nitrogen, and become toxic at relatively low concentrations. Nitrite in turn is consumed by Nitrospira bacteria which excretes nitrate. It's the nitrate you want, that's basically a fully usable source of nitrogen for plants. Nitrate can become toxic, but it takes very large quantities. This is exactly like your fertilizers, they aren't poisons, in fact they are necessary, but in very large concentrations do become toxic. Test kits for all of these chemicals are readily available at your local pet store, and I would also suggest picking up a phosphate test kit as well. You can also get test kits for all the micro nutes, like magnesium, iron, etc, but they get rather pricey. My magnesium test kit for my reef cost me around $70, and expires after around a year. On the topic of test kits, the salifert are reputed to be the most accurate without going to scientific grade probes (these get expensive, but area readily available, as are controllers for them). The powder based test kits are best because they have much longer shelf lives than the liquid test kits.
 

smokendude420

Active Member
the tanks hold less than 2 gallons. i am thinking of getting a sheet of plexi glass and spliting the tanks into 2 or four sections and getting more bettas, i like the bettas due to the fact that there so damn tough and it hasnt died yet, im not good with fish. i started with 4 goldfish and they died ina matter of a week. the "nastyness" i was refering to almost looked like mold, didnt affect th ewater only hte rocks, then i removed the rocks adn got green algea growing right on the rock and on my water pump tube(just at the base of the hose too) kinda hard to describe, i am hopeing that this will turn out ok, the limits of one fish has worried me as far as feeding the plant goes, but i have been keeping it small.

what do you think of adding a coule few more betta withe plexiglass spliters 2 or 4 seperate sectipons?


thanks for the help eh?
 

gobbly

Well-Known Member
hehe, I must have thought the plant was larger then, it looked like a 20g+ in the pic. You might see if you can find some females (look just like the males but won't have the long flowing fins), they are much less common because they just don't look as good, but some fish stores will carry them. They are a hearty little fish (remember, they live in mud puddles), and in that size tank might be one of your better bets. I suspect the goldfish died from heat, they really like it closer to 60f, which strikes me as far too low for your plant (too bad though, they are hardy otherwise, and produce more waste than pretty much anything else). I would not suggest using plexiglass to keep more males, they will most likely harm themselves attacking the dividers to try to get at the other males. Get females to go with your male instead.

Edit: another problem with dividers is that they will severely reduce your water flow, and you want enough flow to keep new water in contact with your bacteria. Opaque plastics will prevent fighting, but will still interrupt the flow of water.

What you are describing as looking like mold is almost certainly a macro bacteria. I was just thinking more about this, and managing macro bacterias and algaes is going to be one of your main challenges, but a really easy way to reduce this issue is to prevent your grow lights from illuminating the tank. Maybe a black plastic cover with a hole that the plant itself plugs up. It will reduce fresh air available for gas exchange, but if you have a good air pump that shouldn't be an issue. You're trying to get decent levels of nitrate and phosphate in the water, and that will encourage these growths, but they also require light, deprive them of that, and the issue is severely reduced.
 

smokendude420

Active Member
good point withth e fish hurting themseleves never though of that, and hte water flow also. i may try it with black plastic if i cant fid the females, how many more woul d you recomend for the 1.5 to 2 gallon tank?

this is kinda an experiment...it has been going well and i have leraned ALOT lol

thanks for th ehelp eh.
 

gobbly

Well-Known Member
You add them one at a time, give it a week or preferably two between adding them. If you have test kits you can tell from those; watch your levels, you can actually see the ammonia rise briefly and then drop as your nitrite rises, and then same with that to nitrate. If it takes a little longer for those substances to peak and drop than last time you added something, then you are at or close to all the system can handle. In the absence of test kits I would guess 3-4 is going to max you out without some medium for beneficial bacteria growth. If you get some decent surface area and water movement, you could probably put 4-6 females with the one you have now... With betas your limiting factors are dissolved oxygen and surface area for microscopic bacteria to grow, they are used to small areas.
 

smokendude420

Active Member
Hello,

I saw some new developments on the ol fishtank weed plant this week, she has started to for her buds...it not much, and prolly wont turn out more than a joint or 2 by the time it is done, but hey its been fun...i have not added nutes, just been feeding more than usual.

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