***** Play It Koi is rated 4.9 out of 5 stars, based on 2248 reviews!

Hakko Diaphragm Kits

13 reviews HK-D25


Sale price $31.00 Regular price $39.00


Our rebuild diaphragm kits are simple to install. They include diaphragms to fix both sides. Refer to our troubleshooting section for directions on proper replacement procedure.

Tools you will need:

- 1 medium Phillips screwdriver

- 1 small Phillips screwdriver

- 1 medium pair of pliers

Note: If your diaphragms are blowing out frequently, you most likely have an excess back pressure problem in your design. Check that your air delivery tube is large diameter and no kinking is occurring. Check your air diffusers for clogging. Ceramic style air stones need cleaning with muriatic acid every 3 months typically. Check that the number of air diffusers is sufficient to handle the air output of your Hakko pump. Too few diffusers will create excess back pressure. Read the article titled "Heat Control for Air Pumps"

View Instruction Manual for Hakko Diaphragm Repair kits (PDF)

Customer Reviews
4.9 Based on 13 Reviews
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Casey M.
United States United States
Great Service and Great Shipping

Play It Koi beat everyone on the Web. The price was the best and the three day USPS shipping was as good as it gets here in the jungles of South Kona, Hawaii.

Play It Koi Hakko Diaphragm Kits Review
Robyn E.
United States United States

Great seller. Arrived quick, good communication

Dennis L.
United States United States

Quality replacement part

Paul s.
United States United States
very easy to replace

The service was very fast and customer service was very nice. The Diaphragm Kit is factory original. Replacing the diaphragms is very easy - this is my second one and they last about a year.

Linda G.
United States United States

Perfect fit. Easy to install

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