Evaluation Of Ocean Free Hydra 20 Filter

Definitely interested to hear your results!!

I was always put off these filter for the simple reason that the electrolysis bit needed replacing regularly, and was quite expensive!

Interested too about your findings.

Hi Folks,

OK, here we go...

Firstly, a little background. I was interested to see if the Hydra 20 could be used to replace the conventional biological filter that we all know and love (!). After all, the Ocean Free Hydro-Pure blurb would have you believe that was the case. In fact, it would go one stage further - not only could this product perform the nitrification process but the de-nitrification process as well. For further information, take a look at https://www.yihufish.com/products/filter/of-hydra-powered-by-hydro-pure-technology/faq/.

I set up a 37 litre freshwater tank with no fish - just water, the Hydra 20 and a heater. Using ammonium chloride crystals, the starting total ammonia reading was adjusted to 0.4ppm. Water conductivity was 330uS/cm, pH = 7.5+/-0.1 and temperature 28.5C +/-0.5C.

Total ammonia remained completely unchanged for the first three weeks. Then reduced to less than 0.05ppm in the fourth week. Nitrite was first detected four days into the cycle, rose to 5ppm and reduced to zero after a further five weeks. Nitrate was first detected one week into the cycle. It then increased to 40ppm during the fourth week and then fell to 2ppm. The whole cycle took six weeks. According to the OF FAQs, it should have taken 14 - 21 days.

I wondered if the Cata-Pure cartridge was faulty. After all, that's the only part that filters the water. Again, according to the Ocean Free FAQs, the electrical resistance of this cartridge is supposed to measure less than 50 ohms. Using a Fluke 73 multimeter, I measured just over 5000 ohms! Despite numerous attempts to elicit an answer from the manufacturers of the Hydra 20 concerning this discrepancy, I was unsuccessful. Technical support rests on the shoulders of just one man who is rarely available.

Last week, I returned my unit to Maidenhead Aquatics for a full refund.

JPC

Sorry @jaypeecee just seen this, yes it is! £68!