Help please - High Phosphate & Algae Bloom

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deanspoors
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Hi All,

So I'm pretty new to fish keeping, so please bear with me and go easy!

I have recently upgraded from a 63l tank to a 200l, it's Coldwater, but I have a heater in to keep it at 18degC it's stocked with;
2 black moors
3 fancy goldfish
8 danios, leopard & zebra
2 bristle nose plecos

I'm using a Fluval 307 external filter, Eheim air200 air pump, Fluval UVC. Fluval Aquasky

So I've had the tank for a few weeks checking the water periodically and all seemed fine for first couple of weeks until BAM an algae bloom. My first beginner mistake was the use of 6 in 1 strips to check for a nitrate spike, all values were within acceptable values so I assumed the bloom had been caused by excessive use of the tank light, I covered the tank up for a few days and bought a fluvial UV in-line clarifier, 3 days later and the water was worse than ever. I visited my local aquatics shop who suggested high phosphate levels. Sure enough after a water test the tank phosphates were off the chart (<10ppm), a quick test of the house tap water also indicated that the tap water is (2-5ppm!)..

At the weekend we carried out a 75% water change, removed all the dragon stone and placed in boiling water, and removed and rinsed the bogwood (too big to boil). I also placed 250g of bagged RowaPhos into my external filter, and we've recovered the tank.

Rechecked the water again today and the algae bloom is getting worse again,
NO3 = 10-25 NO2 = 1 GH = 0d KH = 6d pH = 6.8 Cl = 0 PO4 = >10

and phosphate is still off the chart, what should I do next? I have 1l of Phosguard at the ready, but I'm not sure whether the RowaPhos has already saturated, or just hasn't had time to work yet.

Thanks in advance for the advice!

Dean
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Andys temperate tank
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How big are the fish Dean? I'm not too sure what causes phosphate increases. It may be too much fish poo and or over feeding?
64l kitchen tank: 16 golden tetra.
5ft 425L: 7 blue angel fish, 30 rummie nose tetra, 20 black neon tetra, 1 longfin bristlenose plec, 2 corydoras sterbai, 2 SAE.
deanspoors
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Hi, they're all pretty small right now, I've dropped their feeding to every other day too. The black moors are probably 8cm and the goldfish are probably around 5cm The plecos are both about 4cm.
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Stephen
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Hi Dean and welcome to the forum.

Just an observation.
The water temperature is a bit too cool for Bristlenose plec at 18C long-term.
Bristlenose plecs (Ancistrus sp.) originate in south America and best kept at around 22C-24C
Black Moors are fine up to 24C although cooler is better
Danios (zebra & leopard) are fine at anywhere between 18C-25C.
I would suggest 22C as being a good compromise.

Excess phosphates in the water is often due to over-feeding as many fish foods contain phosphates.
Is the aquarium close to a window or getting direct sunlight?

All the best
425L SeaBray Elite aquarium - Rio Mamoré (Bolivia) theme
4 x Cupid Cichlids, 14 x Cory caudimaculatus, 13 x Cory sterbai 52 x Reed Tetra, 4 x Honeycomb Bristlenose (L519)

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plankton
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Bristlenoses can take down to 18C, probably better at 20C. One of mine is in a 22C tank, the others are slightly warmer, one at 26C, the others at 24C.
Overfeeding is often the cause as above.
Give the RowaPhos time to work before adding anything else.
Keep up with twice weekly water changes to keep it down to tapwater level.
For the algae bloom try a 4 day blackout to get that under control.
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Martinspuddle
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Greetings :] & welcome to AF-UK

Have you tested your water supply for PO4?
WARNING - DO NOT BREED, FEED OR PET THE PUDDLE! :dodgy2:
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deanspoors
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Hi Martin, yes tested and it was way over 10ppm. Since then I’ve used 250ml of RowaPhos and then another 250ml of seachem phosguard, and the phosphate is still showing over 10ppm! That’s after an 80% water change too. I guess the rocks and media are saturated with phosphate. Do I just keep at it with the Phosphate remover?!
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Martinspuddle
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deanspoors wrote: Wed May 26, 2021 15:07 pm Hi Martin, yes tested and it was way over 10ppm.
Not good, and where in her Majesty's kingdom do you reside?
WARNING - DO NOT BREED, FEED OR PET THE PUDDLE! :dodgy2:
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deanspoors
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deanspoors wrote: Wed May 26, 2021 19:46 pmDurham
What test do you use for phosphates Dean? I'm in Sunderland, you've got me worried.
64l kitchen tank: 16 golden tetra.
5ft 425L: 7 blue angel fish, 30 rummie nose tetra, 20 black neon tetra, 1 longfin bristlenose plec, 2 corydoras sterbai, 2 SAE.
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