Those are two totally different subjects The batting is for mechanical removal of particulate matter in the water. It is simply a sieve that catches stuff larger than molecules. Microbes live in it, but they live every where in your pond. The bio balls don't do anything for particulates. They simply provide a living space for microbes that consume nitrates in the water. There are many substitutes for them such as plastic scrubbers, plastic forks, cut up straws, lava rock and many other objects that don't decay in water. They all provide lots of surface area. I don't like the lava rock. It collects too much gunk and is hard to clean and is very heavy and expensive. I do have a layer of scrubbees under the quilt batting. I have never had to add store bought microbes. There are many threads on a search that discuss different bio objects. Bio balls are rarely mentioned. Some people use a single layer of quilt batting and rinse it or replace it every day or two. I just refold the whole thing to fit the top of the Skippy, which gives me about ten layers. I don't have to change it at all during the season unless the critters decide to play in the Skippy. All bets are off then. You might want to do a search on quilt batting, scrubbees and some related subjects here. This can be a definite Hot Topic. What's grass? You mean that stuff that covers 10% of our yard that my DH hates to cut?

Hey there, Deb. I must be missing something. Let me re-state the problem you are having. The fountain is clogging and large amounts of algae are clogging the filter surfaces. Do I have that right? It is unusual that the algae would collect on the filter in such a manner unless you have string algae or some other kind free in the water. Algae needs light to grow and the green color would suggest it is growing or freshly caught in the filter. It must be coming from somewhere. The Hydrogen peroxide is cheap and harmless in the quantity I suggested and would kill string algae and related types. The dead algae would be collected in the filter. It would resemble the green sludge you describe. If the UV light is working properly it would kill other types passing through it and it would collect in the filter as a green sludge, too. Maybe you don't have enough filter material.(?) Where is the pump located? Before or after the filters? If it is behind the filters you have it set up as a pre-filter and that would fill up the filter material pretty quickly. If the pump is in front of the filter material you can eliminate a lot more gunk since it won't close up the pump intake. That is why pre-filters are often made to eliminate only debris that can damage the impeller. Usually the pump is strong enough to break up stuff like algae clumps and pass it along to the filter which becomes a biofilter that can consume the nutrients . If the water is then passed on to a feature like a fountain there is likely to be residue inside the fountain head. It should be cleaned with a brush periodically. A coating of algae on surfaces in the pond is normal. About the only thing that gets rid of it is lots of plant cover or scrubbing it off so it is briefly free floating which clouds the water for a while. Of course the poop from the fishies and any uneaten food is mixed with that, too, so you don't want to stir up a lot of it at once. It is best to use some type of vacumn that can contain the fine mulm. The poop and rotting fish food feed the algae. The UV can only kill what is in the water that passes through it. Maybe we are talking apples and oranges. Tell me about the fountain that keeps clogging. Is it on a dedicated pump or in line with the filters and UV system?. The only time I have had a problem was when I some clear tubing or when I didn't clean the fountain head properly with a bottle brush. You didn't say if you are testing the water with a good testing kit. It sounds like you may have lots of nitrates and nitrites which benefits algae, which precedes ammonia. A decent kit runs about $25.00. It is a good investment. I really want to help you solve your problem Deb. Sorry the first try was not helpful. Sandy

our 5000 has been in for 3 months, so we haven't had to change the filter yet, but the 2-pak of replacement filters (#501) are approx $50 on the auction sites so no worries there. the wire grid appears to be durable enough and aprilaire recommends that they simply be wiped down when you change the media. we also run 2x60w UV above the AC's a-coil and our home air is rain forest fresh. keep in mind that the 5000 cabinet is 12" wide, so you need to consider this for the install (possible duct work, which ain't cheap). all the above said, the 4" merv is a great setup and maintains excellent throughput of air volume and considerably less expensive. it really depends on what you need and how pure you want your air. the 4" merv should remove 90%+ of contaminants from the air. the 5000 will remove 98%+. we thought the additional cleaning % was worth it. either unit would be a HUGE improvement over the standard 1" filters most people use.

Actually, the larger surface area is LESS load to the blower. The filter will clog less and allows more air to pass through because it IS larger. Put it this way - which is easier to breathe through - a straw, or a vacuum cleaner hose? Another factor to consider is the cost of the filters. I was buying the best disposable ones I could get (just one inch, that's how my place is set up) , and with full-time blower operation and a shedding dog, was changing them monthly and they were costing close to $20 each. I bought washable electrostatic filters on sale for a similar price, got two so I can rotate them. How well do they work? Pretty well as far as I can see, the non-dust collecting side seems to stay clean so little or no dust is coming through, I can't remember how many microns they go to, but they seem ok. I'm not sure how long they are supposed to last, I give them a vacuum (central vac exhausted outside so I'm not pumping dust back into house) then wash them well and air dry them.