Wishful thinking but krish do you have any pics of the plumbing on your 75?? That setup is pretty much what I'm going for being first timer
Definately...Here it is all plumbed in and you don't need any check valves. The overflow will only drain what is being pumped into the tank so if the pump is turned off, the water will not drain down the overflow anymore until the pump is turned back on. The only thing that needs some sort of provisions is the return line. Most people will drill a small hole right below the water line in their return spout so when the power is cut to the return pump, once that hole is exposed to air, it will break the siphon otherwise that return line will continue to drain water until the head of the nozzle is above water level. Some people use check valves, but they need to be maintained so drilling a hole to break the siphon is mostly used. K...Here's how mine worked...
Here is a shot of the CPR overflow hanging on the tank. The little pump sitting on top is the aqualifter and all it does is suck water out of a tiny nipple on top of the overflow and drains it back out the other end.
This shot shows how much space it all takes up inside and outside of the tank
Now this shot shows the beginning of the drain which you can see to the back of the overflow to the bottom. All you'd need is a piece of hose, flex spa whatever to attach to the overflow and go to the sump. The flex hose you see I used there was this
http://www.globalpets.com/ProductDetail.jsp?LISTID=175C0000-953663625 but regular hose will do as well just make sure use clamps.
This shot shows how water enters the sump. This was my sump before I expanded it. Real simple design, but I used a bulkhead with a piece of pvc pipe in it so I could attach the hose. Some people will even just rest the hose in their sump and that's it, but I like things a bit neat so I used the bulkhead. On the other end of the bulkhead in the sump, I went to a straight piece of pvc pipe with a Tee on the bottom (rather than the elbow you see) which prevented any noises from water entering the sump. I can fetch a pic of that as well if you need to see it
Now all you need to do is to get water back to the tank. This shot shows my return pump and the return line which was just regular vinyl hose I clamped onto the pump (if you are wondering why the sump looks different here, it was taken after I expanded it, but this was the best shot to see the return pump
) On the other end of the hose, I used a sea swirl for randon flow, but a simple return nozzle you can buy is this
http://www.premiumaquatics.com/Merc...uct_Code=SQUID-UTUBE&Category_Code=Wavemaking It comes with the hole already drilled as well to break the siphon so you just attach your hose to it and you're done. Let me know if that helped