Bullfrog – Brand Review

Bullfrog – Brand Review

Bullfrog :

Bullfrogs, like most bands, are a bit of good a bit of bad and a bit of ugly. Those goofy pods really limit the area where the jetting can go. and are so expensive to replace $400-$700 that according to the dealers I have talked to very few people ever replace them. The whole premise is kind of whack, on any hot tub with good high flow Jetting you can change the Jets and customize a chair for $20 $40 a jet and you have more options because each jet can be swapped and it can be done simply and easily.

And they are still haunted by the horror stories of the bacteria build up behind the pods in their earlier models, this caused them to have to tap into the jet pressure to flow a lot of water through

the back of the seat to keep the area sanitized which takes a lot of the water flow away from the jetting.

The shell is an ABS plastic backed acrylic which is not my preferred construction. Hailed as the new way in the 80’s these Shells have been abandoned by most of the industry. These types of shells usually can’t even hold their own weight with water and people over time so they need to use pedestals and props to support it just to stop it from falling apart. The insulation is good, and the components are good, and the plumbing is good but that pitch about the reduced amount of pipe increasing the flow rate is questionable science. they are inferring that the water is flowing a shorter route but 90% of the pipe is in parallel so the actual distance between the pump and the Jet is similar to an efficiently plumbed spa. I ran the numbers using the rough data and according to these figures the actual friction reduction loss in the large 2″ pipe pushing 300 gal/min is almost .5 PSI per foot. Their claim is based on the idea that they reduced the amount of plumbing thereby reducing the friction loss and thus improving the efficiency. But the science disagrees because once we hit the manifold (I removed flow effects through the manifold because both systems use them) we split off into an average of 16 smaller 3/4″ pipes carrying an average of 18 gals per minute with a friction loss of only around .36 psi per foot.

They reduced the total amount of pipe by moving the manifold right behind the seat and only using small 3/4″ hoses for the 6″-12″ between the manifold and the jet. this means they actually use more of the big2″ pipe that actually has a higher line loss per foot. it’s this crazy marketing world we live in… now we could tweak the numbers to make either scenario look slightly better or worse, I used rough numbers that would be typical of these pumps and pipe and I used the same rough numbers in both calculations and I think the reality here is there is very little significant difference in the performance of the two systems but here is one big question… If they saved so much money on all the plumbing and pipework why is it not a mid-priced spa??? Mayhaps they went the route of spending lot of money selling pseudoscience and gimmicks instead of spending it on building a great hot tub…

 

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Just Joe
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Just Joe

Chris; do you perchance have an updated photo of the piping(interchangeable backs) that Bullfrog now uses?

admin
Admin

Yeah, I saw it. They basically replaced the smaller pipes going to each jet by making it an integrated manifold… when I did the calculations for line loss the worst was the large 2″ pipe from the pump to the manifold, the flow rate through the smaller 3/4″ pipes from the manifold to the jets were actually lower loss per foot so really they took out some of the pipes where it was more efficient and replaced it with more of the 2″ pipe that was less efficient 🙂 I don’t think they really made much difference in the overall… Read more »