This is just forward some INFORMATION OF "Bacterial Counts in Reef Aquarium Water" in the link show below. I don't need to create the other post for discuss, this is just
FYI only if you are curious about bacteria in the saltwater. I will copy and paste some of main point only, you can read them all in the link.
http://www.advancedaquarist.com/2011/3/aafeature
3.1 Baseline bacteria counts
The initial experimental foray in reef tank water bacteria enumeration was focused on establishing baselines for bacteria populations under different husbandry regimes. Later, these baselines will be used as comparison points in experiments where the system is perturbed, either by carbon dosing or by mechanical filtration (skimming, GAC). Much prior effort in the area of bacteria counting from authentic reef water has led to an expansive body of work. A few representative examples are documented in Table 1, where bacterial counts from reef water in Hawaii, Micronesia, Key Largo, and the Northern Line Islands all converge on a span of bacteria populations in the 500K - 1500K/mL range or so. The counts from the Northern Line Islands, Ponape Island, and Key Largo were derived from epifluorescence microscopy measurements, whereas the Kaneohe Bay data were acquired via flow cytometry. In addition, we sampled water from a mangrove estuary in the Florida Keys, and not surprisingly, this highly sedimented shoreline water exhibited a bacterial population (3300-4400K/mL) much higher than those observed in the more pristine reef waters. These values serve as standards for comparison to aquarium water, and they will help address the question, "Are our reef tanks similar to, or different than, an authentic reef with respect to water column bacterial populations?"
A second series of bacterial counts focused on control water samples of various origins. These data represent low-end standards that delineate the limits of our counting technique. For example, every experimental run was accompanied by an RO/DI/0.2 um filtered water blank to ensure that the flow cytometry instrument itself was not a source of bacterial contamination. It did not seem to matter whether these samples were treated with formaldehyde preservative or not; similar counts were obtained in both cases. Overall, these "sterile" water blanks typically displayed counts in the 1000 - 5000 bacteria/mL range; occasionally, values as high as 10000 bacteria/mL were observed. Since bacteria counts of authentic aquarium or marine water samples were 1-2 orders-of-magnitude greater than these blank values, we concluded that instrument contamination was not likely to increase the measured bacteria counts in any significant way. Both Aquafina bottled water and the RO/DI water produced in the 175-gallon aquarium make-up water system were almost sterile: < 1500 bacteria/mL. State College Pennsylvania tap water, on the other hand, did carry a modest bacterial load; 27K/mL.
The surveyed reef aquariums divided into two distinct sets of husbandry protocols; aggressive and passive (see Fig. 6 for pictures of these aquariums). The aggressive husbandry practices included protein skimming, GAC filtration, and regular water changes in an active effort to scrub the water of nutrients. The passive approach did not involve any of these procedures. Interestingly, the aquaria subjected to passive husbandry exhibited bacterial counts that fell within the range seen on authentic reefs; 200 - 1000K/mL. On the other hand, the tanks that "benefited" from careful attention to nutrient removal protocols displayed bacteria/mL counts that fell far short of these numbers; only 90-140K/mL. In addition to monitoring water column bacteria counts, the TOC (Total Organic Carbon, see Feldman, 2008) levels were examined as well. Not surprisingly, the tanks with "unpurified" water exhibited TOC levels greater than those seen with the skimmed/GAC-filtered tanks. The "purified" aquaria's TOC levels fall within the typical TOC range seen on authentic, healthy reefs (Feldman, 2008); the passively husbandry tanks were 2-3x higher.
The observation that, at least among this small set of aquaria examined, the water within the skimmed/filtered tanks had only ~ 1/10th of the population of bacteria that the unskimmed/unfiltered tanks had was a real surprise. It speaks to one aspect of aquarium husbandry in which a perhaps important parameter (?), water column bacteria counts from authentic and healthy reefs, is not reproduced at all effectively in these home aquaria. Sensitive corals, like
Acropora, do not thrive in the high-bacteria-count/high-TOC-level tanks examined, although soft corals do well (see pictures). On the other hand, SPS corals do well in the low-bacteria-count/low-TOC-level tanks (Fig. 6). These observations raise a number of questions, chief among them perhaps are, (1) "Do water column bacteria counts have any relevance to the short-term or long-term prospects for maintaining SPS in captive aquaria?", and (2) "What is the relationship between TOC and water column bacteria population?" The former question, whereas perhaps more interesting, remains unanswered. The latter question (TOC vs. bacteria population), which bears on the topic of carbon dosing, will be addressed below.
Table 1. Bacterial counts from authentic marine water, various control samples, and several reef tanks.
Look the table in the link
The reef aquariums that were monitored for their bacterial populations:
Figure 6a. KSF 175 gallon reef tank
Figure 6b. SJ 500 gallon reef tank
Figure 6c. SJ 55 gallon reef tank
Figure 6d. SJ 29 gallon reef tank
The bacteria/mL counts for the aquaria described in Table 1 reflect single-time-point measurements, and it is possible that hourly, daily, or other fluctuations in bacterial populations have been missed. These modulations in bacterial populations might result from the light on/off cycle, food additions, pH swings, etc. In order to probe this point, a few week-in-the-life longitudinal studies were conducted on both the 175-gallon reef tank and the 55-gallon reef tank. The first experiment covered 5 days of typical aquarium life, with the skimmer deliberately off for the first three days, the UV sterilizer on, and the GAC and GFO filters on, Fig. 7. Over the course of this experiment, the water column bacteria population fluctuated between ~ 95K and 115K bacteria/mL, a ~ 20% spread in values. The skimmer was turned off at t = 0, and the count rose steeply over the next 12 hours, and then declined to the starting point at the 2-day mark. At that point, a gradual rise to the maximum recorded value, 115K/mL occurred. Turning the skimmer back on at the 3.5-day mark may have slowed the rate of this increase slightly, but the data are not compelling on this point.
It is temping to attribute the initial steep rise to a presumed corresponding increase in the carbon source TOC, since the TOC-removing skimmer was turned off at t = 0. During this growth phase, nitrogen and phosphorus nutrients as well as C would be stripped from the water column also. In this interpretation, the subsequent decline in bacteria population at the 12-hour mark might reflect a depletion of these N and P nutrients required for bacteria population growth; that is, perhaps the initial growth spurt might reflect an increase in C concentration (skimmer off) in a C-limiting bacterial growth regime, and the subsequent decline at 12 hours might indicate a switch over to a N and/or P limited growth regime. This hypothesis dovetails nicely with the Carbon Dosing ideas described earlier. However, it is important to appreciate that simply observing the expected result of a hypothesis does not validate that hypothesis - the strongest conclusion that legitimately can be offered is simply that the data is consistent with the predictions of the hypothesis. Other interpretations of the bacteria population data in Fig. 7 cannot be excluded at this point. Furthermore, the "rebound" in bacterial growth after 2 days is more difficult to interpret without some further knowledge about commensurate C, N, and P levels in the tank. A more controlled experimental plan to monitor bacteria population change contemporaneously with C and N concentration measurements might settle this issue; this experiment will be discussed shortly.
Figure 7. Bacteria/mL counts from a 175-gallon reef tank (See Fig. 6) over the course of 5 days. The tank was fed 3-4 times/day (PE mysis shrimp, Hikari mysis shrimp, flake food, and pellet food) during the "on" part of the daily lighting cycle.
One concerning point in the experiment described in Fig. 7 involves the role that the UV sterilizer might play in influencing bacterial levels; Are we killing significant numbers of bacteria by UV treatment, thus suppressing population growth? The UV sterilizer in use is a 57W flow-through model from Aqua Ultraviolet. In order to probe this question, we re-ran the "week-in-the-life" experiment with the UV sterilizer off, but the skimmer on continuously, Fig. 8. The observed bacteria/mL values over the course of 5 days fluctuated between 60K and 90K (~ 50% change) for this particular time period. Thus, there did not appear to be any significant bacteria population increase in the water column when the UV sterilizer was off, and it is probably safe to conclude that the UV sterilizer does not have a significant effect on the bacteria population levels in the tank's water column.
Figure 8. Testing the influence of UV sterilization on bacterial populations in the water of a 175-gallon reef tank. The feeding regimen described with Fig. 7 was used in this experiment as well.
A final "week-in-the-life" experiment was conducted on the 55-gallon tank lacking any active filtration, Fig. 9. In addition, this tank had been treated daily with vodka as a carbon source for 6 months prior to water removal. This vodka addition started after the original bacteria population reading reported in Table 1 was taken. Since there was no active bacteria removal mechanism (i.e., skimming), it was not clear, a priori, how the bacteria population might change compared to the pre-vodka value of 590±70 K/mL. In fact, the bacteria population clearly had risen to a significantly higher level than observed in the pre-vodka time period, and now it hovered around 1500-2500K/mL. Once again, significant (~ 60% !) fluctuations in bacteria/mL counts over time appear to be the norm, at least for the two aquaria examined.
Figure 9. Bacteria/mL counts from a 55-gallon reef tank (See Fig. 6) over the course of 5 days. No protein skimming or GAC filtration was employed on this tank. The tank was fed frozen mysis shrimp daily. In addition, a vodka dosing regime of 4 mL of 80 proof/day (= 3 ppm of C/day) was in place for 6 months.
Overall, the major conclusions from these preliminary studies on baseline bacteria counts are
1. Actively purified aquaria have water column bacteria populations that are approximately 1/10th those of authentic healthy reefs.
2. Unpurified aquaria have water column bacteria populations that are approximately the same as those of authentic healthy reefs.
3. UV sterilization does not significantly influence aquarium water column bacteria populations.
4.
There is substantial fluctuation (20-50%) in the measured water column bacteria populations over a several-day time scale in aquaria.