View Full Version : Tunze 9400 Skimmate?

05/10/2017, 08:28 PM

I've had my tank setup (JBJ 45) for probably a month and a half. When I first installed the skimmer I ensured the pump was hooked up correctly. I had the air valve all the way open during the first few weeks. During this time the lid would constantly pop up and down bc of all the bubbles/air flow. Now I have the air flow restricted somewhat so that the lid doesn't pop up and down. Still I don't have any skimmate production. I have cleaned it out twice, but never had any skimmate build up. I'm sure that it is broken in this far in, but I can't figure out the problem.

What am I doing wrong? This is my first skimmer. Any advice?


05/11/2017, 08:44 AM
What is in the tank at this time (inhabitants), if the population is sparse and feeding is infrequent their may just be very little to skim. The main things to check are the depth of submersion, I find the ideal is around 1/3rd of the intake submerged. With the setting the air can be more open. I assume it is producing bubbles? When there is skimmable material if you closely watch the bubble column you will see two distinct layers of bubbles, one which is large white bubbles which are just bubbles, the layer above will be a more frothy yellowish foam, it has a consistency similar to meringue, this is the actual waste that we want to go into the cup. Many additives can affect skimming as well so that is another possible culprit, usually mineral supplements are no issue, but amino, vitamins, stress coat, dechlorinator, coral foods, etc can all have an impact and that is usually no skimming for a few days followed by very wet skimming.

05/11/2017, 12:00 PM
Thank you for your reply. Currently this tank is pretty new. The only inhabitants are some Peppermint Shrimp, Blue/Red Leg Hermits, several snails and a blue damselfish. I only feed once a day. Nitrates were getting high at around 15 ppm so I just wanted to see if maybe the skimmer should be pulling some waste out of the water despite the low bio load. I positioned the skimmer further up with about 1/3 of the intake submerged as you have suggested. The air intake is open also. At this point it is not bubbling over so that's good. Hopefully I can give it a week or two to give me some results, but I recognize that perhaps my bio load is simply too low.

05/11/2017, 12:02 PM
No additives have been added to the tank. Just normal fish feeding once per day. I plan on adding several more fish and some coral over the next two months and just want to ensure the skimmer is working properly. Self-admitted newbie lol

05/11/2017, 01:16 PM
No problem at all, we all start somewhere.

First on the Nitrate, keep in mind that until you get into really high end test kits, most hobbyist grade kits don't actually test Nitrate they test total nitrogen, some of the better ones will give a correction factor but even that is a rough idea. Lamotte and Machery Nagel kits will generally give actual Nitrate and if you run both you will see that the kits that test actual Nitrate detect almost nothing in most cases compared to the total N type kit. These basic hobbyist kits are useful for seeing a trend but not for an actual definitive number. Personally I have been very pleased with the results of carbon dosing on Nitrate but I would get some experience before getting into that as it has its own potential problems, but biopellets or vodka dosing or using Calcium acetate as your calcium source are all potential ways to do this. My hunch is your actual Nitrate is likely in the 0-5ppm range.

While you would definitely have skimmable waste, you need to have enough to build a stable foam head that can be pushed into the cup, I suspect that in normal day to day this is too low to happen. You could dry a food lower in fats and higher in cellulose and chitin, but I wouldn't do this exclusively as the fish need a diversity of foods. One food that almost always enhances skimming is freeze dried krill and you can crush it to the food size your fish need. It would just be a way to test if you get a better response and prove the skimmer is working as it should. Conversely fatty foods will tend to inhibit skimming to some degree.

05/11/2017, 01:33 PM
Thanks very much for your quick replies Roger. Your insight has been very helpful. One more question if you don't mind. Should my collection cup be full of water? The skimmer is producing foam and bubbles that are spilling into the cup but it is all water at the moment. Is that normal?

05/11/2017, 01:41 PM
Close the air slightly, try 1-2 turns to start and then after that try a half turn waiting a few hours between adjustments, the results are not always immediately apparent.

05/11/2017, 01:50 PM
Okay will do. How will I know when the air has been closed enough or if it needs to be opened more? Should the collection cup be dry with just the foam spilling over into it? Apologies for so many questions. Thank you again.

05/11/2017, 02:02 PM
What gets in the cup should look like iced tea, still watery, but with a definite color to it, that could be whitish, greenish or brownish depending on what is in the water to skim out. When you have it tuned right you will generally see, though this won't always be consistent so I would go more by what collects, that the big air bubbles come about 1/3rd to half way up the riser in the cup and the remainder is a fine frothy foam.

05/11/2017, 02:56 PM
Okay great. I'll give the skimmer several days to a week to see if there is any change and hopefully I can find the right setting for optimal performance. Thank you!