phosphate problems in planted tanks

[Priscacara]

G'day, I first noticed a lot of my plants in the discus tank looking "sunburnt" a few weeks back and its getting worse. It was suggested by the lfs to check phosphate levels, something I havent done before as I never added anything I could think of that may contain it. I got a shock! All 2 of the tanks with plants in them have phosphate levels at least 5mgl. The discus tank has eco-complete substrate with some 3mm gravel, the other 2 tanks just have gravel. The plants are all low maintenance types such as swords, crypts and annubias. The plants in the other 2 tanks are still doing fine despite the high levels of phosphate but I do have a lot of on glass algae growth ( no surprise!). I also used a product called dinosaur dung a large tablet type aquarium plant fertilizer in all 3 tanks, that and feeding are the only common denominators that I can think of. I tested the tap water and there is zero reading on the test kits so it has to be something I do. Overfeeding shouldnt be a problem but always hard to tell how much but it all gets snapped up in abut 30 seconds in all the tanks.

I've been doing daily 20% water changes in the discus tank with no visible change in the test results which to me means either something is constantly leaching it or it was so far about the 5mgl that its going to take a while to make a diference.

I ws thinking of trying carbon in the discus tank but unsure if that would work or not. Bio-chemzorb is something else I had planned on getting for that tank but again not sure if its of use for this particular problem.

Any thoughts or info will be much appreciated.

Cheers!

[Priscacara]

Bit disappointed with no replies but most probably aren't running planted tanks. I have done further testing and pretty sure the culprit is my ph down. I tested the water I was about to add to the discus tank and phosphate was 5.0 mgl or above, tap water straight had zero, tap water with dechlorinator had zero but as soon as I added ph down it was above 5.0.

The only suggestion by the lfs was to get a CO2 system running on it, not really much point as I've already lost the majority of $500 worth of plants and cant replace them. I would also have to modify the output of the filter for less surface aggitation which could also have already contributed to the death of the plants if it removed any available from the water.

[Todd]

i think a RO/DI system would be the best way to fix the problem.

[Priscacara]

Tx Todd, I used to run RO back about 20 years ago and would have liked to do it again but cant afford it. I'd also still have the problem using ph down but I will look into it for pricing.

[CThompson]

Hi, what fish food are you using,? Check the phosphate levels in that. Also, what sort of rock are you using? Some rocks for example, if were gathered (by you or a shop) from farming areas, can soak up the phosphate like a sponge (basalt did it to me) and release it into your tank. So gravel could be a culprit too from that angle, do all three tanks have the same substrate? Put some in a small container with non-pho tap water and test every few day. Your phosphate will be coming from somewhere, my first guess is substrate, then the food. Try to sort out how it is getting in, if you fail, then use some sort of commercial phosphate resin to suck it out.

Don't know why the shop suggested a co2 system, unless they wanted your money. Not sure why you are talking about sodium bicarbonate either as this won't affect the phosphate.

In the mean time, preprepare water, and do water changes big enough to swap out the phosphate.

[pseudotrop]

I think pH up is sodium (bi)carbonate and pH down is sodium bisphosphate from memory.

[shelly]

As said above ph down is sodium biphosphate, so ph down contains phosphate.

I use ph down as plant food. I find it to be useful with plants only as it will increase tds and most low ph fish prefer low tds over low ph.

Also if yr looking for feedback on planted tank questions try aquarium life forums they are the best for plants. This place is the best for cichlids.

[Priscacara]

Tx for the input! There is different substrate in the 3 tanks and I did the test on it over 2 weeks just on the off chance there was something in it but no change at all in the tests.

I just got delivery of a non phosphate based ph down I'm going to try out, also got daily liquid carbon to add to the tank (Flourish and API's Co2 Booster to use once the flourish is used up). I also got API's Leaf Zone for weekly dosing of the tank. After talking to Ben at Age of Aquariums its highly likely that all the nutrients in the substrate were used up rapidly as I had very fast growth rates initially and I probably didnt supply enough to keep them going after that.

I'll still need new plants but hopefully will see improvements in what I have left.

Thanks for the Aquarium Life suggestion, I have them bookmarked but not a member yet so never thought to go there.

Cheers!

[waruna]

What do you exactly mean by "sun burnt"?

PO4 is a very important (macro) nutrient. If everything else is in balance you will need to keep your PO4 levels at the right level, most high tech planted tanks are regularly supplemented with PO4. I currently run a 1000l high tech planted tank with 16 Wild Discus, i add 8g of KH2PO4 (Mono-potassium Phosphate), four days a week.

If you are spending $500 on plants i think you'll need to learn some basic points in plant care... Greg Watson's ebook is a good starting point;

http://www.aquaticplantnews.com/

I can understand why your LFS suggested to purchase a C02 system, i would have done the same.. The average person does not spend that much money on plants, if you are having no success then the next step is Co2, lighting and ferts...! I believe Co2 is the single most important factor for healthy plant growth.. Saying that you will need sufficient light and ferts/nutrients combined with Co2, everything has to be in the correct ratio..

Aquariumlife is a good forum for plant nuts

Good Luck

[Priscacara]

Sorry for late reply, tx for the input Waruna.

The tank is as low tech as I could get it and the plants were those that would do well in lower light, I chose them specifically for that reason. The lighting is 4 x 55w compact tubes specifically for plants, filter is a fluval fx5 and the substrate is eco complete and 3mm aquarium gravel.

CO2 is great if you can afford it but unfortunately I cant. $500 may sound a lot but when a sword is on average $25 it doesnt take long to add up.

I have seen some decent improvement now that I have started using flourish/co2 booster liquid along with a weekly dose of leaf grow nutrients, it came too late for most of the plants but its a lesson learnt. I did as much research as I could but as always there is a diversity of methods used and I may not have taken it all in properly.

If I hadnt already spent so much on getting the tank to this stage I would forget all about plants and have none at all, the stress and outlay has been more than expected and havent had much enjoyment from the project to date. This will change of course, the fish are great and used to me now so they come investigate when I do water changes instead of hiding a bit :-)

Tx for the links and the advice everyone, always appreciated.

[Priscacara]

Thought I would add a quick pic of the discus tank as it is now with some new growth occurring. Bit out of focus unfortunately, the rippled pale colored plant with rippled leaves in the back right (Aponogeton vanbruggenii, MT lace plant) has almost tripled in size over about a week.