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  1. I think it really depends on your nutrient input into the system. Denitrification bacteria uses carbon, nitrates and phosphates to reproduce in accordance with the Redfield ratio of Carbon 106: Nitrate 16: Phosphate 1, and this ratio is how the bacteria introduced by both systems (and other probiotic systems) uptake your nutrients. As you can see, carbon is the one that's taken up the most, and phosphate the least. The whole supporting theory behind probiotic systems is that all of our systems end up carbon limited. The bacteria in our systems use up all the carbon and are unable to process any more nitrates or phosphates, since with 0 carbon they cannot uptake any more nitrates or phosphates to reproduce. Add to that the fact that we constantly introduce nitrates and phosphate into our tanks via fish food or other additives, and we see a build up in these 2 compounds. Probiotic systems thus encourage the adding of carbon to start the bacteria uptake for reproduction again. With lots of carbon added, the bacteria can once again process all 3 compounds to reproduce. The reason we add bacteria on a regular basis is to speed up the process (more bacteria, more uptake quicker instead of having to wait for the bacteria to naturally reproduce). Once the increased population of bacteria quickly depletes nutrients down to limiting levels again (likely carbon limited again, since we rarely end up with exactly 0 nitrates or phosphates), "excess" bacteria dies off and is either skimmed away or used by our corals and other invertebrates as food. This process begins again the next time you dose your carbon source and additional bacteria (or in the case of "permanent" carbon sources like biopellets, it keeps on going). The above is my understanding of probiotic systems and how they work to maintain ULNS. In Zeovit and Ultralith systems, we have the additional use of zeolite stones to adsorb nutrients. This helps to control the rise of nutrients by adsorbing various compounds such as ammonia (I'm not sure what else zeolites can adsorb, but I know some zeolite stones adsorb ammonia), which would reduce eventual nitrate creation by your usual bacteria crew. This ideally reduces the amount of carbon and additional bacteria that need to be dosed. That zeolites are very porous is also a benefit as it creates more room for bacteria to colonise and take up nutrients. However, the use of zeolites in my opinion acts as a buffer against large increases in nutrient levels, and doesn't detract against the basic concept of probiotic systems as I outlined above. Now how does this all affect the use of PO4 removers? We need to remember that phosphate is the compound that is least taken up by bacteria. only 1 unit of phosphate is taken up per 16 units of nitrate and 106 units of carbon. Hence, the compound that would be the least likely to ever hit limiting levels would be phosphate. This is why most of us face problems with phosphate, but not nitrate. For some tanks, this is ok - they feed sparingly pellet food or self prepared seafood mixes that are low in phosphate. This low addition of phosphate plus water changes work well with probiotic systems to keep phosphate levels low enough to qualify for ULNS. However, some of us also are too busy to prepare foods, and some of our fishes only eat frozen. Some of us just throw entire cubes of frozen mysis into the tank. The water that such frozen mysis is frozen in is usually quite dirty and very high in phosphate. Maybe some of us feed pellets that are high in phosphate too, or use tap water to do our salt mixes. All these introduce phosphate at a higher rate than is being taken away, and we may end up in situations where carbon or nitrate (unlikely) reach limiting levels, and thus there is no further phosphate uptake by bacteria. Even if we keep dosing more and more carbon, it's useless once nitrates run out. In the second situation, we end up with a situation that most of us are familiar with - rising phosphate levels. It's not the fault of any of the probiotic systems. They are doing their job. But they are limited by the Redfield ratio and how the bacteria uptakes nutrients. In situations like this, I think that the use of po4 removal media is necessary. Your tank system is at an inbalance where the introduction of phosphate is at a rate not consistent with nature (i.e. the Redfield ratio), which is why you are suffering from rising phosphate levels. Use of po4 removal media is simply to rebalance your tank back to natural levels and does not "compete" with bacteria in any way. An alternative to this that I have seen some reefers use is to actually dose nitrate back into their system while increasing carbon dosage. Theory is the same - to achieve back nutrient balance in your tank. If Phosphate balance is out of whack, you either reduce phosphate to achieve balance, or increase carbon and nitrate accordingly to achieve balance. Both achieve the same result. In fact, dosing nitrates back may have some added benefit as nitrate is usually dosed back using Potassium Nitrate (KNO3), a common fertilizer chemical used in planted tanks. Most FM and Zeovit users test for and dose Potassium to achieve better coral colouration. Hence, dosing nitrate to reduce phosphate also has the added benefit of dosing Potassium. Hence, in my view, neither Zeovit nor FM is wrong. Zeovit envisions an ideal situation where your tank is in balance and thus discourages the use of po4 removal media - because in a balanced tank, removal of PO4 makes PO4 limited and inhibits the removal of nitrate and makes carbon dosing excessive and unnecessary. In this case, yes, removing po4 would compete with your bacteria. FM on the other hand envisions a more practical/realistic scenario where our tanks are not balanced and thus it is inevitable that you have to remove PO4 from your system since it will never be in balance. This is also why FM doesn't encourage the use of PO4 reactors constantly, but the use of UltraPhos *when needed*. UltraPhos is to be used until PO4 levels drop to desired levels, then removed and not used again until they rise again. Based on the above, my opinion is that use of PO4 removal media should be determined by the user themselves on a "as needed" basis. There's no right or wrong answer, just what is right for your tank in your current situation based on how balanced the nutrients introduced into your tank are. My $0.02, happy to be corrected if I am wrong
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  2. Free tang , if the person not collect today will open to free to any one can collect today.
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  3. Recently bought a yellow fiji leather.
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