Switched to Power Heads for UGFs – Update 1/7/17


One of two AquaClear 1000 Powerheads in my 18-gallon (filled to 10-gallon level) tank. This is the only powerhead I’ve found that’s suitable for my small tanks (largest is 10 gallons). These powerheads are rated “for aquariums up to 10 U.S. gallons.” The critical factor is the flow is adjustable. At full strength, the flow is still too strong. However, at the lowest setting, the flow is perfect. The price is also unbelievable — $8.50 U.S. in Hawaii. Prices may vary elsewhere. Mahalo, Namruso, for your tip! I finally made it down to Petland in Kahala and bought some of these. As you say, they’re perfect for small tanks. I wish I had done it sooner.


Setting it up in the tank was a bit of work, requiring trial and error. I wanted to have the head sitting above the surface to monitor the flow of water. This required some awkward jiggling, but I finally got it to work. Gone are the unsightly air pumps and tubes. Gone is the constant noise. These babies are silent. I also added two of these to the 10-gallon on the kitchen counter. Finally, I replaced the air tube in the 5-gallon Fluval Chi UGF with one of these powerheads. I hope this will reduce or eliminate the salt crusting.

[UPDATE 1/7/17 – After 6 months, I’ve given up on the powerheads and returned to the good ole air pumps. The current was just too strong for my small 10-gallon tanks, which are really filled to the 8-to-9 gallon level. I noticed that opae activity had been declining progressively to the point where they were no longer swimming about. As soon as I made the switch, they became more active again.

The powerheads seemed to reduce the salt crusting a bit, but the cost in terms of tank health was too great. The powerheads also had a tendency to slip off their rubber mounts on the tube. This was a danger to the opae that wandered too close. They were sucked into the powerhead and churned into chum. I didn’t always notice the problem until many hours had passed. I tried to stabilize the seating by shoving a short length of plastic tubing over the oval intake and placing the whole back into the uptake tube. This worked for three of the powerheads, but not for the fourth, which kept slipping out of the tube.]

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Glass Jar with Lid: New Opae’ula Tank

Added coral in a condo formation rather than a substrate.

Added coral in a condo formation rather than a substrate. In the 1.5-gallon oblong tank on the right, the coral is arranged as a substrate, completely covering the gravel bed.

Here's a view of the air line protected by a pair of rubber shims.

Here’s a view of the coral condo from the top, with lid removed. You can also see the air line protected by a pair of rubber shims cut from a clear plastic hose. The orange blurs in the tank are the opae’ula that I just added.

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Build Your Own UGF

Updated 3/4/16

Found this 1-gallon glass jar with a lid at the thrift shop.

I’m setting up a 1-gallon opae’ula tank in a glass jar I found at a thrift shop. This tank is about half done. It shares an air pump with the oblong 1.5-gallon tank that’s partially visible in the background.

Opae’ula are fun to raise. Since they don’t need much space for a simulated natural environment, we can be creative in building tanks. I believe a gallon jar is about the smallest optimal size. At a thrift shop, I found a 1-gallon glass jar (see photo above) with a lid and decided to turn it into an opae’ula tank.

Since there’s no opening for an air line, I raised the lid at one end about a quarter of an inch to insert a line. Since the lid is made of glass and a bit heavy, I added two rubber shims on both sides of the line to prevent the lid from crimping it. I made the shims out of two quarter-inch wide rings cut off from the end of a large plastic hose. Cutting through the ring at one point creates a u-shaped shim that will fit over the bottle edge.

The tank is not quite ready for opae. Thus far, I made a UGF out of a plastic cover (see photo below of a similar cover) and a spare plastic tube, covered it with gravel, inserted an air line into the exhaust tube, and added brackish water from one of my established tanks. I’ll be adding a coral substrate over the gravel next before adding a small colony of opae from the 18-gallon.  Continue reading

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Diatom Stage Is Tied to the Coral — Not the Tank


The 18-gallon illustrates an interesting phase in the progression from diatom to green algae growth. I added another layer of coral to the existing condo a few months ago. In the photo above, the older layer of coral is visible underneath as green and the newer layer above as reddish brown. I had assumed that the diatom stage occurred only once in a tank and that additional coral would simply evolve from white to green. But apparently the diatom stage is a necessary part of the green algae growth process for any new coral introduced into a tank.


Here’s a closer view of the difference between the two layers. I extended the condo to accommodate the additional small colonies from the tanks that I decommissioned earlier.

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Adjusting the UGF to Reduce or Eliminate Salt Crusting

Updated 2/4/16, 2/22/16, 3/6/16

5-gallon Fluval-Chi with a redesigned UGF system. The airstone has been removed from the exhaust tube, eliminating the bubbly foam that I believe is the cause of salt crusting. on the outer edges.

5-gallon Fluval-Chi with a modified UGF system. The airstone has been removed from the exhaust tube, eliminating the bubbly foam that I believe is the cause of salt crusting on the outer edges.

My 5-gallon Fluval-Chi is the tank that refuses to die.

After giving up the year-long battle against salt constantly crusting on the top outer edges of the tank, I moved the colony into the 18-gallon, with plans to decommission the Fluval-Chi. However, I was unable to net some tiny juveniles that hid in the gaps in the gravel substrate. I decided to keep the tank running, with no coral condo or lava rocks, until they grew large enough for me to net. The tank is bare, except for the substrate and UGF.

I had lowered the volume of water in the tank by about 50%, but salt crusting was still a constant problem. (The water level in the photo above is higher because I added water after the modification.)  Continue reading

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Opae K-Pop ‘Ula

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After the Bubble Scare

10-gallon as of 1/30/16.

10-gallon as of 1/30/16 (Fuji X100T).

Perhaps the upside of the bubble scare is the aftermath, when I have a chance to mull over my original goals in entering this hobby and make some decisions about how I’ll proceed for the foreseeable future. Yesterday, after a full day of observing the 10-gallon, I concluded that the opae’ula were bubble free and returned the quarantined members to the tank. At about 1:00 this afternoon, I took the photos in this post. The tank is as it was prior to the scare.

Close-up of the 10-gallon on 1/30/16. Nikon D5500.

Close-up of the 10-gallon on 1/30/16 (Nikon D5500).

My original purpose in entering this hobby was to see if I could create a low-maintenence self-sustaining and self-perpetuating environment that would come as close as possible to Dr. Wayne Nishijima’s bottles and Dennis Nakashima’s natural tanks. Both neither fed the shrimp nor used artificial filters. Nishijima’s water was, I assume, from the anchialine pool where the opae were collected. Nakashima’s, from ocean water diluted with tap water. Both neither cleaned the glass nor did water changes.  Continue reading

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