Pond Soil Substrate - Do I Add Monthly Fertiliser?

[nmonks]

Hello --

I have a tank with a pond soil and gravel substrate topped with silica sand. Plant growth is pretty good, given the lighting (two full length Tritons). Then tank has been running since May of last year. Does pond soil fully replace the need for fertiliser, or should I be adding some every month? I'm assuming the pond soil has some iron, etc., but does adding fertiliser help?

Cheers,

Neale

 

[jimbooo]

Hi Neale. so as not to misadvise you i need to know your tank size in US Gallons and the wattage of your tubes. also are you injecting co2 either via pressurised or yeast based kits? if so what is your co2 level.

the above will have a huge effect on nutrient uptake rates if it's a high uptake level then yes you will need to add ferts.

by the way i read your substrate and glassfish articles in PFK last night, very impressive. just so you know the dates on your website are wrong for the articles. the issue month your articles appear in is one month behind that quoted on the site. no biggie just thought i'd let you know.

if you can answer the tank questions i'll do my best to advise on ferts.

James

 

[jkc]

Hi Neale,

I was thinking about using exactly the same substrate you have and just wanted to ask, do you have any problems with the sand falling through the gravel?? Does it still look neat??

Thanks

James

 

[nmonks]

James, James,

Thanks for the replies.

The tank is 180 litres (~47 US gallons), with a sloping substrate about 35 cm (~13 inches) deep at the shallow end and 50 cm (18 inches) deep at the deep end.

No CO2 injection. The water is acidic (pH 6.5) and pretty soft (~7 degrees GH, less than 3 degrees KH).

The lights are two 30W Tritons with aluminium reflectors. They're on 12 hours total, with a 2 hour siesta.

At the shallow end is Vallisneria "spiralis" type things, and some Bacopa monnieri, as well as a couple of potted Echinodorus "mixed species" that are not doing well and basically hanging in there throwing out the ocassional leaf but not much else. In the mid depth of the tank is a huge mass of Cabomba that regularly takes over the aquarium, and a couple of Nymphaea stellata "red tiger" that are doing very well too. At the deep end are the Java ferns and some more Bacopa.

There's a picture below to give you some idea. It isn't a perfect planted tank by any means, since I have a lot of fishes in there -- 17 cardinals, 9 glassfish, 3 Corydoras, 3 Synodontis nigriventris, 3 small gobies, 1 big goby, 4 hatchets, 8 halfbeaks, a ram, a puffer, and a 15 cm Panaque.

Cheers,

Neale

PS. Will go back and correct the stuff on my web page. Thanks for the heads-up! Glad you liked the glassfish article; it was fun to write, and they're definitely among my favourite fishes. Sadly under-rated and, let's face it, abused when it comes to dying them.

PPS. No, sand doesn't vanish into the gravel. Some does, and fills the gaps, but most sits where it is. The roots from the plants quickly stablise the substrate, just as they do the wild. The reason I used gravel around the rocks at the bottom of the heap was simply to create the hillock quickly. Sand would slide away and so all go to one flat level. With lava rock, coarse gravel, and then sand, I could build up a significant hillock that stayed where it is. I then scattered some gravel on top, and the effects is really cool: you get patches of sand and then patches of gravel, just like in a real river.

 

[George Farmer]

Your substrate, tap (?) water, fish food and waste should provide most if not all the nutrients necessary.

Are you displaying any nutrient deficiency symptoms? If not then I wouldn't bother with adding any liquid ferts as this may upset the apparently decent balance that you have acheived.

Bacopa monnieri prefers higher lighting and harder water IME. I'm not sure why your sword may not be doing so well, I'm assuming you've removed from the pot prior to planting? How well is the Vallis doing? Is is it the twisted leaf variety (spiralis is straight leaf - the roots are twisted hence the name)?

Do you have any issues with excess anaerobic build-up in your deeper substrate i.e. Hydrogen sulphide?

 

[nmonks]

Well, I use rainwater mostly, so the water itself is likely to be mineral poor. I add a little tap water just so the pH does fluctuate wildly, but not much.

So far no obvious nutrient problems (you mean like yellow leaves, that sort of thing?). But I have had some other problems. The pH and hardness may be the issue with the Vallisneria -- at first it went wild, and needed regular cutting back. At that point I was using tap water (high pH/hardness). Then I switched to rainwater, and at one point about 75% of the Vallsineria died, literally within a week. Tissue-like leaves, hair algae on everything. (I don't seem to get hair algae on healthy plants. Odd that.) The Vallisneria are the spiralis, straight-leaf kind that get to about 60 to 90 cm long if you let them.

The Bacopa was an experiment. In the wild actually does well in brackish, by the way. You often see it in coastal pools and stream, very close to the sea (i.e., on the beach!). It seems to be doing okay in terms of growing, but one thing is that it sets its roots out very slowly, so always seems to be being turfed up. Anyway, it isn't doing well, but isn't dying either.

No H2S problems in the substrate (yet). I put this down to having lots of catfish to clean up, but most especially to Malayan livebearer snails, which are fantastic for this kind of set-up. They burrow quite deep, and constantly aerate (if that's the word) the substrate.

Re: Amazon sword; no, it's in the pot. It was some silly variety pot that had at least three different species and separating them out without damaging the roots looked impossible. So I left them in the pot. I actually potted the Cabomba, too, because otherwise the Panaque turns them out of the sand overnight.

Cheers,

Neale

Your substrate, tap (?) water, fish food and waste should provide most if not all the nutrients necessary.

Are you displaying any nutrient deficiency symptoms? If not then I wouldn't bother with adding any liquid ferts as this may upset the apparently decent balance that you have acheived.

Bacopa monnieri prefers higher lighting and harder water IME. I'm not sure why your sword may not be doing so well, I'm assuming you've removed from the pot prior to planting? How well is the Vallis doing? Is is it the twisted leaf variety (spiralis is straight leaf - the roots are twisted hence the name)?

Do you have any issues with excess anaerobic build-up in your deeper substrate i.e. Hydrogen sulphide?

 

[George Farmer]

That answers the Bacopa and vallis issues then, too soft water. Have you considered adding more tap, this will obviously stabilise your pH too. Interesting on the Bacopa/brackish issue, I knew it prefered harder water but brackish.....

The sword will do better unpotted so root growth is less restricted. You can cut back the old root growth considerably without long-term damage to the plants. Just try to keep enough root so it can reach the soil. Push the plant all the way to the tank base, then pull up an inch or so to allow the roots to point in an appropiate direction. Does that make sense?

Cabomba will be fine in a pot. It extracts most of its nutrients from the water column. If you find you have too much growth you can always eat it - it's a local vegetable!

I have MT snails too. Great maintenance crew.

The reason you're not getting algae on healthy leaves is due to the allelochemical production by plant growth. This is why I believe a tank full of healthy, growing plants will very rarely suffer from algae issues. It also explains why adding seemingly copious amounts of nitrates, phosphates, iron etc. to a high light/high CO2 tank won't induce algae - despite what Mr Walmsley claims.

 

[nmonks]

Re: Bacopa in brackish....

Check this out:

http/www.hear.org/starr/hiplants/images/...pa_monnieri.htm

 

[George Farmer]

Re: Bacopa in brackish....

Check this out:

http/www.hear.org/starr/hiplants/images/...pa_monnieri.htm

Cool.

 

[nmonks]

I agree; my nitrates run from 50 to 100 mg/l. I have a lot of fish, and I certainly feed them a bit more than they need. But algae remains much less of a problem now than it did when I started the tank, had fewer fish, and lower nitrates. The difference is the plants are growing briskly. They can't be using the nitrates up, since the nitrates are high. So what you say makes sense.

I'm coming around to the view that the solution to algae is plants. Whatever the aquarium, use plants. I don't think it really matters if you have a "green thumb" or not... hornwort seems to be a really good algae buster and has zero requirements. Ditto Java fern. So there's a plant for everyone.

Time to get writing your aquarium plant book, I think!

Cheers,

Neale

The reason you're not getting algae on healthy leaves is due to the allelochemical production by plant growth. This is why I believe a tank full of healthy, growing plants will very rarely suffer from algae issues. It also explains why adding seemingly copious amounts of nitrates, phosphates, iron etc. to a high light/high CO2 tank won't induce algae - despite what Mr Walmsley claims.