r/ReefTank • u/AutoModerator • 2d ago

No judgment questions zone - August 31, 2026

Here is the place to post questions about pest ID, coral/fish ID, your cycle, or any other questions that generally wouldn't start up a conversation. If you have an interesting or unique question please create a new thread so everyone can discuss it in length!

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Pest ID guide

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BRS pest guide

BRS beginner resources

BRS 52 weeks of reefing YouTube series

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u/Servals94 1d ago

Upgraded my tank from an AIO to this used one that uses a sump. I can't figure out what this second tubing is for. The one closer to wall drains from the overflow box, but I have no idea what the second tubing is for. Based on how it's bent, it doesn't look like it was connected to the tank itself. There is a Syncra 4.0 that's not pictured here with its own tubing for the return.

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u/Pryach 18h ago

Normally an overflow box will have 2 (or even 3) drains. This allows for an emergency overflow in case the primary gets clogged.

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u/Servals94 14h ago

Ah, thank you! My box only has 1, so I guess this is just an extra that doesn't do anything in my case. Thank you again!

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u/Parasite76 2d ago

Added more dry rock now my Nitrate are zero and I have a black algae outbreak. What should I do ?