12-16-2010, 12:29 PM
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Originally Posted by rdwj
First, I'm finding this site really useful as I study up on the hobby. It's a great community with some really good resources.
I'm trying to work out what basic equipment I'd like to have in my first tank and I think I'm sold on housing what I can in a sump. There are a couple of things that I'm having some difficulty understanding and I'm hoping you may be able to help.
- I don't get the automatic top off feature. Doesn't the sump dictate the level of the water in the main tank by design? The way I understand it, the height of the skimmer cup determines the low water point and as long as the return pump has water to pump, it will reach that point. What am I missing? How does adding a top off section change anything?
- What, if anything, needs to be done to balance the amount of water entering your sump from the tank and the amount the pump is returning to the tank. Seems to me that there is only so much flow you are going to get into the sump based on the width of the pipe - and the pump needs to either match that or be a little slower. How do you know how powerful of a pump you need or do they have an adjustment?
That's it for now - I'm sure there will be a lot more to come
here's my opinion on the matter.
1. ATO is not required for sure, however you will have to check on a regular basis on your water level and add as evaporation take place in your tank. this may not sound like a big deal and it isn't to some, but remember this is every single day. the water level in the sump will get lower and eventually the return pump will suck air and send it to the display tank. keep in mind that if you go on vacation, holiday you will have to get someone to check for water level as evaporation is 24/7/365 everyday! so if you choose to not use a ATO get a relative big sump so you won't have to check as often.
2. as far as flow thru the sump i personally i don't like a fast flow because it can cause uncontrollable micro bubbles to return into your display especially if your sump is on the smaller size. i have a 100 gallon tank and i'm using a 700 gallon pump which after you consider head pressure and such it's probably around 500 gals/hr. to me it's best to get a smaller return that is efficient power wise (to keep electricity cost down) and have a decent skimmer in the sump. the balancing will take care of itself. if you put a pump in the sump and pump water into the display the water level will rise and return to the sump simply by overflowing into the prefilter. unless you are using some ridiclous size pump you should be alright. most overflows are rated for like 700 gals/hr. so if you have 2 overfolw prefilters you can expect it to handle 1400 gals/hr.