There is no reason for 2 x 300 on your tank. If the older one was about to die and you got a newer one, all you needed to do was to move the media from the broken to the new and save the parts from the older filter that are still able to serve as repalcements if needed (intake tubes, the lid and other useful parts). Adding a filter adoes not create more bacteria. At best it spreads out the existing amount of bacteria between the two filters.
The bacteria live immobilized in a biofilm attached to hard surfaces and out of direct light. The total amount of bacteria will increase or decrease in response to a change in the ammonia loading in a tank. When there is more than they need, they multiply faster than they die. if there is less ammonia, they reproduce ever slower until the colony shrinks to the size that thrives on the reduced ammonia level.
So, when we add a filter to a tank we are just giving the bacteria more choices of where to live, but the addition does nothing to increase the amount of bacteria. By leaving two filters for a bit of time in a tank that had only one you are pretty much insuring that moving one of the filters will mean moving about 1/2 the combined bacteria they contain. Depending on the tank that can be a bigger or smaller part of the total bacteria in a tank. It lives anywhere it can get what it needs delivered to it.
Have you tried doing a decent cleaning on the older filter? Have you checked the impeller to see if when out of the filters it spins smoothly? I have had the magnetic cylinder on the impeller split open on a canister impeller. Can you tell if the impeller shaft is bent at all? These things are cheaper to have replaced than a whole filter.
Aquaclear 20, 30, 50, 70 Shaft Regular price $ 4.69
Aquaclear 70 Impeller Regular price $15.29
Just as an FYI- the AC 20, 30, 50 and 70 all use the same motor and shaft. What differs in the models is the impeller. I have owned a lot of ACs over the years. I still have 18.I have never had one quit as in not be fixable for much less than the cost of a new one.
The bacteria live immobilized in a biofilm attached to hard surfaces and out of direct light. The total amount of bacteria will increase or decrease in response to a change in the ammonia loading in a tank. When there is more than they need, they multiply faster than they die. if there is less ammonia, they reproduce ever slower until the colony shrinks to the size that thrives on the reduced ammonia level.
So, when we add a filter to a tank we are just giving the bacteria more choices of where to live, but the addition does nothing to increase the amount of bacteria. By leaving two filters for a bit of time in a tank that had only one you are pretty much insuring that moving one of the filters will mean moving about 1/2 the combined bacteria they contain. Depending on the tank that can be a bigger or smaller part of the total bacteria in a tank. It lives anywhere it can get what it needs delivered to it.
Have you tried doing a decent cleaning on the older filter? Have you checked the impeller to see if when out of the filters it spins smoothly? I have had the magnetic cylinder on the impeller split open on a canister impeller. Can you tell if the impeller shaft is bent at all? These things are cheaper to have replaced than a whole filter.
Aquaclear 20, 30, 50, 70 Shaft Regular price $ 4.69
Aquaclear 70 Impeller Regular price $15.29
Just as an FYI- the AC 20, 30, 50 and 70 all use the same motor and shaft. What differs in the models is the impeller. I have owned a lot of ACs over the years. I still have 18.I have never had one quit as in not be fixable for much less than the cost of a new one.
