Why overflow?

[fishy&co]

Hi,

My tank has two bulkheads drilled direclty into the side of my tank right at the very top. I never have an issue with sound because the water isn't falling it just get sucked down the outlet. I don't see this on any other tanks and i wanted to know why? Originally I asked the aquarium builder to drill the holes in the bottom however he gave me this spiel about it being stupid as the glass would crack (it's not tempered) which i guess equivilates to him being to lazy. Just curious as to what I am missing out?

thanks

[Steverino]

Are the holes near each other? He is right about some not being tempered glass on the bottom. If it was drilled at the bottom, you need a permanent overflow box that goes top-to-bottom, taking up more room in your tank. Bulk heads near the top require just the smaller overflow box up near the top, or you could actually go simple and have just a screen or inlet mesh and let it drain right into the bulkhead. I have seen several tanks where the reefer has the top-to-bottom overflow box, but the bulkhead is near the top of the tank anyway. The holes near the bottom make me nervous in case the overflow box cracked or leaked and your whole tank drains out. Unless you had a stand-pipe setup, in which case the drain hole is near the top anyway, right? Two top bulkheads also allow you to use one for incoming water, one for outgoing, without having anything hanging over the top of the tank.

[fishy&co]

Thanks for you reply steverino,

ATM they have those standards guards on them. Are there any advantages to building a small overflow around the bulkheads? I've run it like this for a year and never had any issues.

[Steverino]

I am not the expert here on this subject, but the little boxes around the bulkhead can reduce the gurgling and splashing noise if done right and can skim just the top surface of the water, and are less prone to blockage, say if you had an anemone that could cover the hole. An anemone could not cover the box.

[NALCOMIS]

snails will block the holes too, I would definatly put a box there. Also it surface skimms the water, very important IMO.

[fishy&co]

Thanks for your replies,

I can't find any snails where I live unfortunately and the guards would stop anything I have from getting in, I guess surface skimming would be the definate advantage in my case.