Oct 15, 2000, 10:45 PM
Post #77 of 312
Let me try to answer your questions.
High Nitrates Level? Try This!
[In reply to]
1. When a drip tray is used to distribute the water, what is the relationship between the size and number of holes to the flow rate of water?
First of all, allow me to define the word trickle from the dictrionary as :
1. to issue or fall in drops;
2. to flow in a thin gentle stream;
3. to move or go one by one or little by little;
4. to dissipate slowly.
The efficiency of the system does not solely depend on the no. of holes or the size of the holes appearing on the drip tray or PVC pipes. It does however, depends alot on the the way the water is delivered to the surface of those bioballs. Hence a too slow a flow rate will cause all the water to comes together after passing thro' the drip plates and defeat the whole purpose of using a drip plate. However, if the flow rate is too fast, there will be little time for exposure before the water returns to the pond hence depriving the trickle intake of oxygen. That goes the same with holes. Too small a hole, water will be diff. to pass thro' and too large a hole, it defeats the whole purpose. My consideration will therefore be the *break point or at the balanced point where water drip thro' the holes in the drip plate. In order to do this efficiently, you need to have a valve to control the flow rate and a water level of at least 3 inches or more above the plate.
2. Twice Mark has mentioned that a slow flow rate is best or at least not detrimental but suggests a rate of 1.5 Ė 2 times the pond volume per hour. To me, this is a fast flow rate when wet systems are often only 0.5 times the pond volume per hour. Am I wrong on this?
You can achieve this by either expanding the surface area of the filter and the drip plates or cutting down the flow rate with slower pump.
3. If the object is to supply as much air into the system as possible why put it in a container? Why not just set up a fountain right in the pond cascading water over bio balls in a perforated tray at itsí base just above the water level of the pond? If the water supply to the fountain was mechanically filtered what would be missing?
Water trickling need not confine to only bioballs sitting in a filter tower. High Waterfalls and fountains are another form of trickle system. The whole idea is to exposed the water to as much oxygen as possible before returning them to the pond. Unfortunately not many of us have big area to install these. Noise another consideration as we do not want to disturb our neighbours. Hence trickle tower seems to be the answer and besides its easy to maintain.
4. When the filter size is referred to in tonnage, what is meant? The water is not accumulating in the Ďdryí filter system, so what is being referred to? Is it the potential volume of water the container could hold? Shouldnít filters be rated by the amount of surface area they supply?
Surface area has our main consideration when coming to size of a filter system. And we usually take 30% or more of pond surface area as an indicator. If we calculate the total surface area of the bioballs, we will quickly realised that how small our filter tower is as compared to the normal wet system.
Hope these help.
(This post was edited by Mark Richman on Apr 10, 2001, 9:00 AM)