Phosphates

[recycled oldy]

My tank has had high phosphate problems for some time with the expected side effects of algae and cynobacteria. My lfs obtained readings, "off the chart" and nothing we tried seemed to help. Even 25% water changes using RO water only reduced it temporarily. Xmas brought me an API Phosphate test kit and I have now made several checks, one of which was a sample of gravel left over from the original bag, never used in the tank. I put this in RO water for 36 hours and obtained a phosphate reading of 10ppm or higher. A similar test on gravel from the tank, which had been thoroughly washed before use and in the tank for 9 months, provided much the same result.

It appears that I will have to change the gravel, (although a major job in a 200l planted community tank) and ask for members advice on where I may obtain natural, (not technicolor) phosphate free gravel in the 3 - 4mm size range. This size to prevent the Aquabase or laterite leaching out into the water, which was an earlier problem! Preferably a supplier within a reasonable distance of Taupo but that is not essential.

I have also wondered about using PhosEx Ultra and would be grateful for members advice on that possibility although given the size of the problem it would probably be unable to cope.

[Sophia]

what sort of gravel is it that you have in there? can you post a photo?

[alanmin4304]

Mostly phosphate comes from food

[recycled oldy]

Hi Sophia, It's just a gravel that I foolishly, (with hindsight) bought from a sand and gravel mechants yard. Nice size, mixed colour, looks great but oh dear! Ph about 7.5 and phosphate over 10ppm. It's a learning curve! but I still cannot locate a reliable source , see my wanted post.

[recycled oldy]

Hi Alan, not in this case, as limestione will slowly but surely raises the PH something in the gravel quickly raises the phosphate level.

[F15hguy]

Hi Sophia, It's just a gravel that I foolishly, (with hindsight) bought from a sand and gravel mechants yard. Nice size, mixed colour, looks great but oh dear! Ph about 7.5 and phosphate over 10ppm. It's a learning curve! but I still cannot locate a reliable source , see my wanted post.

I have used one of the common river gravels sold at landscape suppliers and its always been good for me. although if you got the one commonly sold as "hokeypokey" or Waikato gold, then you may have problems with it as it is extremely porous and tends to absorb whatever leeches into it

are you using any pH adjusting chemicals??

[recycled oldy]

Hi Alan, my apologies, I was rather hurried and made a mess of my last post which should have read:

"Not in this case, just as limestone will slowly but surely raise the PH, something in my gravel quickly raises the phosphate level."

I believe that a mineral/stone called apatite can do that, maybe there is some in my mix.

[F15hguy]

does it look like this??

also has anyone ever used Aluminium sulphate to remove phosphate in an aquarium, it works well in ponds (sold as Phosclear by Ellis and Company LTD), but I've never tried it in an aquarium

[Sophia]

Hi Sophia, It's just a gravel that I foolishly, (with hindsight) bought from a sand and gravel mechants yard. Nice size, mixed colour, looks great but oh dear! Ph about 7.5 and phosphate over 10ppm. It's a learning curve! but I still cannot locate a reliable source , see my wanted post.

I presume with all the testing you did, that you tested plain water that hadn't been in contact with the gravel yet?

[recycled oldy]

Hello F15hguy, yes it loks exactly like your photo. Had the same problem?

[recycled oldy]

Hi sophia, all tests were done with RO water using clean glass jars previously rinsed with RO water. the first gravel I tested has never been near the tank but was some spare kept in the sack it came in. The second test was gravel out of the tank washed thoroughly before testing. PH7.5. Phos. >10.

[Sophia]

This is what I have in various forms.

http://www.centrallandscapes.co.nz/prod ... lders.html

Also Petstuff101 on Trademe will send you some aquarium safe gravel for a price, but the gravel itself isn't too badly priced. The landscapers are usually cheaper though.

[F15hguy]

ours comes from Taumaranui, it has a bit of pumice (annoying) and a few sharp edges (most are round) and is rather dirty. but is cheap and does the job well, use it myself and never had a complaint about it

did you wash the silt out thoroughly??? depending on the source the silt may be the issue.

personally I have never run into gravel that leaches phosphates, it would not be good for landscaping as it would promote weed growth, the opposite of what landscapers want gravel for.

maybe try landscaping gravel from a different shop

[Dana]

Where are you based? I'm midst the same nightmare.

[F15hguy]

Hello F15hguy, yes it loks exactly like your photo. Had the same problem?

sorry, missed this post, that is the one called hokeypokey, waikato gold or waikato colour and imo it is way too pourus, and it has probably been contaminated at some point.

[reef]

Phosphates are in tap water , Whilst using RO is ok ,most of your gravel and rock will leach Po4.

Best to do a big water change with RO water again and them put in some Deltec Po4 remover which is iron based and safer than aluminum based removers.

When using po4 removers i would also add some buffers as they will drop your PH.

[recycled oldy]

Reply to Dana, sorry about late resonse, I am in Taupo, AR980 planted tank less than a year old.

Since my original post I stripped and washed out tank on 20 Jan., new JBL Aqua-basis, new gravel, (from aquarium shop) 40% new water of which half was RO. scrubbed rocks before re-using and threw out any dodgy plants. Next day added PhosEx ultra to filter. 12% water change on 18th, 20% on 22nd.15% on 25th, 10% on 27th. Throughout this, test results have remained at PH 7.4, KH 4.5, GH 4, Phos.has dropped from 10+ but only to about 7. I even bought a food grade bucket for top up use only. There is nothing left to change and the PhosEx Ultra does not seem to be working.

Although using API test kit I am beginning to mistrust the test results. Is there anything at all which could falsify Phoshate test results?

[F15hguy]

btw I soaked some of our Waikato colour (Hokeypokey) in a cup of water for a week, and got a 0 phosphate reading,.

what food are you using????

Are you using the Activated Carbon pads (some brands of Activated carbon can leach phosphates, bu as far as im aware not to this level)

[recycled oldy]

I checked my new gravel, (from S.Island) in rain water for 24 hours and it tested 0. Also tested the basalt rocks.

Food, mainly TetraMin tropical flakes, occasional Sera 'O-nip' stick on tablets also occasionlal Nutrafin Max sinking tabs to ensure the corys and otocinclus get food. Last year I also fed de-frosted bloodworms, (without straining off the water which I now know to be bad). The above foods are either or, not all at once!

No carbon filters at all.