i have been running the k4's for 2 years now and have been impressed with the flows and reliability. i found some mod topics and decided to do them on mine to see how they performed and i am blown away by the difference. with the maxijet 1600 mods these power heads easily turn 3 times the previous amounts and use virtually the same electricity. if any one has one and needs more flow then its worth the time and money. 1 can easily handle the flow for a 75 gl tank.
Can you provide the link for the mod topic. I am running Maxi Jet Mods all around but the one thing that I do not care for is that they tend to develop start problems over time when used on a controller. Are your K's used on a controller?
i cannot find the link to the page that was discussing it but here is a link to the impeller kits i used. http://www.marinedepot.com/ps_ViewItem~ ... F1551.html there is not cutting or real mods. its kind of a plug and play type scenario. i can give quick step by step instructions as to what i did 1. remove the koralia shroud and pull the impeller out 2. remove the prop and magnet off of the impeller shaft 3. replace the original impeller shaft only back into the base of the koralia 4 4. pull one of the rubber ends off the maxijet impeller and slide everything off the impeller shaft 5. place the white bushing onto the koralia shaft and slide into the base 6. install the maxijet magnet impeller 7. choose and install either the black prop or the white(i used the white) and replace koralia shroud. thats all there is to it and takes less then 3 minutes per power head for 2-3x the flow. i did have a problem with both of the pumps starting in reverse but stuck my finger in the prop and it reversed and has been running great since then. in the even t of a power failure they may start backwards again but i am not sure. in total i have an estimated 6000 gph turn over out of 2 power heads pulling around 18 w each versus the stock rating of around 2400 gph at 15 w.
One of the things that I thought was appealing about a Korella mod over a maxi jet is that it comes with a magnet and the maxi jet magnet mods are are not cheap. It is hard to purchase a magnet that is as much as a pump, but I have to say that they hold like nobodies business.
My experience with Koralias has been unreliability and dead fish. The holes in the housings are big and when the powerheads are off, fish swim in. Powerhead back on = dead fish. Most any AC powerhead will have startup problems on a controller since they can start up backwards.
Can you not have them turn off but just run slower. My Tunzes never shut completely off, you set the controller to say 30%, then 60% and they well run up and back inbetween those percentages at setable intervals.
Tunze's are D/C and can be easily speed-controlled and only spin one direction. The first Koralias were A/C and not controllable. A/C powerheads have a 50/50 chance on the spin direction on startup. They now have D/C Korallias that are controllable.
