Where did the phosphates come from....?

[Sands_88]

On Thursday I bought a second hand tank with fish, substrate, plants and ornaments included.

I initially didn't clean anything, and chucked everything back as it was on the other lady's house.

Yesterday I began to clean (stupidly didn't check water parameters before) as there was absolutely huge amounts of algae - she told me hair algae but I think its actually black beard algae.

I cleaned:
rinsed out all the filter media and pipework which was blocked (in tank water don't worry!)
Scrubbed algae off the glass
Scrubbed as much algae as I could off ornaments
Removed as much of the algae from the plants

I haven't cleaned the sand as I thought it probably has a huge amount of BB in - and I wasn't really sure how to do it, vacuum obviously sucks it right up!

The tank was quite overstocked but today I sold 2 large clown loaches and a striped raphael catfish to my mum this morning so is now much much better (Aq advisor reckons about 60% stocked now)

Readings -
Temp 24 celsius
pH 8
Ammonia 0
Nitrite 0
Nitrate 10
Phosphate >5

I haven't fed the fish since I got them, and obviously they had a 100% water change from moving. Where has all the phosphate come from!?

Is it in the plants or alage or sand or ornaments?! Would it have built up in the water from being overstocked in just 2 days?

 

[Masha]

My guess would be that sand. Apparently phosphates can come from decaying algae, fish waste, excess food...

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[Sands_88]

Whats the best way to clean it now its in the tank? Take it out and clean a bit at a time and hope I don't have a mini cycle? Whats the easiest way of doing this now?

Algae is almost growing as I watch because the phosphates are so high lol! (I know phosphates don't cause algae, but they definitely speed up its growth) I scrubbed it all off the glass on Friday and this morning its back!

I don't really want to resort to chemicals or chemical filtration because it won't solve the problem.

 

[Masha]

How about careful, thorough gravel vacuums? If you do a bit at a time, it shouldn't kick up too much into the water column. You will suck up some sand, but just keep it, rinse it, and put it back when all is done?

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[Sands_88]

Good plan I shall give it a go! Thanks

 

[Masha]

Good luck!

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[Noviceafter2yea]

Love that you sold the fish to your mom! Lol

 

[Sands_88]

Well she came round to look at the tank, and I was just explaining/moaning that someone who was going to buy them had let me down, and so I couldn't move my tiny glowlights from my other tank in case they got eaten by the raphael or just died of poisoning because the tank was overstocked...

So being the lovely person she is, she said if I caught them she'd put them in her tank. I went round to see them last night - they look very happy!