High Phosphate Levels

[chemflex]

I carry my water changes out once a fortnight using RO water. At the moment the phosphate levels of the water in my tank is 5.0 and the pH is 6 everything else is normal.

I've tested the water from my RO unit and there's no phosphate in it.

There's hairy algae growing in the tank. The water temperature is 25 degrees celcius and the lights are on for 8 hours (8:00-1200 then 16:00-20:00)

Any ideas?

 

[semper fi]

do you have powerheads in the tank? does the tank get natural light also?

 

[chemflex]

The only power head is the Jewel filter that comes with the tank, it doesnt get any natural light as it is at the back of the room away from the window, any other ideas ?

 

[semper fi]

surface agitation can help to promote the growth of algae. that is why i was inquiring about the powerhead. lowering the powerhead under the water's surface would help to remedy the problem.

 

[chemflex]

The powerhead on the Juwel filters is already quite low down from the surface. What should I do about the pH levels?

 

[K-Holed]

Areating the water may help a little. Large amounts of disolved co2 in the tank can cause a drop in pH. If you're woried about your phosphates being too high you could try giving your substrate a good clean, next time you do a water change using a simple syphon action gravel cleaner and also do more water changes.

 

[tstenback]

what decor do you have in the tank. what is the PH of the water you add? The phosphate level is probably the main cause for the hairy algae. Do you overfeed? How often do you vac the gravel?

 

[chemflex]

I gravel clean the tank at every water change, once a fortnight. The pH of the water going into the tank is 7, it's RO water. There's absolutely nothing that I can think of that could be causing it.

IT'S REALLY ANNOYING ME!!!!!

 

[tstenback]

How about the feeding part? what do you feed the fish, how often and how much. Food is a major way of phosphate getting into the system. How about other decor in the tank?

 

[chemflex]

The decor is slate, ocean rock and live plants. The fish get fed once a day and al the food's gone is less than 1 minute. All 3 of my tank have the same decor and feeding regime. This is the only tank with a real problem.