electrical outage question

whats the point of everyone calculating the overflow of the refugium when you can just install some check valves to prevent the overflow and allow you to utilize more of the volume of the refugium tank?

am i missing something?

 

The "swing" check valves that is mostly used because there are no metal parts,only a plastic flapper with rubber around it is not considered trustworthy, if it fails then you have a flood on your floor. If you leave enough room in your sump for the drainage from the dt then you stand a much better chance of not having the flood. I have a check valve on my return line but also have enough room for the drainage back in my sump.

 

No, you're not missing anything, but there is a rationale to avoiding checkvalves. The point of not using checkvalves is to simply remove another possibility for a component to fail. I can think of a couple of reasons to "floodproof" your system without checkvalves. First, checkvalves can fail. Secondly, you canutilize more of the volume of your refugium without check valves if done properly. Keeping any siphon-producing tubes very close to the water's surface (such as returns, gravity feeds for coiled denitrators), will prevent the need for check valves. Additionally, a siphon break hole drilled into such tubes immediately below the water line will break the siphon. Another point is that a check valve adds head pressure, meaning you'll have to use a more expensive return pump to compensate.

We're all familiar with Murphy's law: Is something can go wrong, it will, and will at the worst possible moment. As a corollary to this, I've found two things to be true: first--the simpler the design, the less prone it is to failure; and, a task accomplished with less potential points of failure makes for a better night's sleep.

 

excellent! thank you so much for the responses. im currently working on drawing up different ideas on my plumbing and refugium setup for my new 75 gal reef tank. i have so many questions....

 

You're very welcome! There's no shortage of answers here at 3reef!

 

Check valves and drilled holes fail, never rely on either to prevent a flood. The only sure method of backflow prevention is an air gap. This air gap is created when the level of the display drops to the returns and they are exposed to atmosphere. This is an easily calculated volume of water and your sump/refugium can be designed around that amout of freeboard or extra volume needed to contain a backsiphonage or backflow in a power outage.
Think of a saltwater reef aquarium as a wastewater treatment plant, they are very similar in that they both contain foods and bacterias which break those foods down into nitrates and export them. We avoid check valves in a wastewater plant like the plague for the same reason, they fail and leak causing problems you don't even want to know about.

 

yeah, totally took the ideal of the check valves out. working on figuring out which compartment of the fuge im going to put the mud/sand and such