What were your biggest purchase mistakes?

[Reefpins10]

Purchased a 1-150W Coralife Pro for $550 at King ED , and paid for a brand new Tunze 6055, I should have bought a used one here on Canreef for a much cheaper price, and found out it was too small for my tank later on

[Zoaelite]

Hydor Magnum 8... Do not purchase these if your tank is less than 6' long, you could probably use them as small boat motor.

[Chaloupa]

Originally Posted by Reefpins10

Purchased a 1-150W Coralife Pro for $550 at King ED

I'm with you on this one....I paid over $700.00 for my 24" 150w x 1.....and was thrilled....mind you it's still going strong over my 65g hex after 7 years...so I guess it's doing ok. But about 2 months after we bought it, there was a huge price drop and we could've gotten away with paying only what YOU paid!