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- 16 Dec 2011
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Ok so first thing is to get a ph tester? Where is the best place to get one of these?
skeletonw00t said:Ok so first thing is to get a ph tester? Where is the best place to get one of these?
ceg4048 said:Well, like all algae, BBA love CO2 just as much as plants do. But having CO2 24/7 means nothing if the output of your CO2 device is unstable, which DIY CO2 techniques usually tend to be. You still need to look at the concentration profile of the tank as a function of time in order to give you a clue of when the CO2 is at it's highest, medium and lowest levels.
The problem is not that BBA love CO2, but that that BBA do not care about whether the CO2 is stable or not, while plants do care and suffer if it is not stable. BBA in a way can sense whether or not the plants are responding well to the CO2 profile. Think of BBA and any algae in the same way that you think of predators such as lions or wolves. If the prey is healthy then the predator will not attack, but if they can determine that the prey is weakened and vulnerable then they attack immediately.
You are correct n that BBA tends not to go away even if you improve conditions so you need to evict it from the tank, normally with liquid carbon and/or a lot of elbow grease, however, if you have not improved CO2 stability, then it will return with a vengeance.
You need to look at the CO2 profile by taking the pH measurements first and foremost. You might discover something you were unaware of.
Cheers,
Well, I mean, you already have a pH test kit, don't you? The fluid used in your dropchecker is a pH test kit unless you are using that all-in-one blue liquid. But if you are using clear 4dKH water and if you then add that orange liquid to the checker then that orange liquid is the pH reagent and you should have received a color chart with that reagent.skeletonw00t said:Ok so first thing is to get a ph tester? Where is the best place to get one of these?
ceg4048 said:Well, I mean, you already have a pH test kit, don't you? The fluid used in your dropchecker is a pH test kit unless you are using that all-in-one blue liquid. But if you are using clear 4dKH water and if you then add that orange liquid to the checker then that orange liquid is the pH reagent and you should have received a color chart with that reagent.skeletonw00t said:Ok so first thing is to get a ph tester? Where is the best place to get one of these?
As much as people winge about pH, I'm amazed that there aren't more folks using a pH meter. Just have a look here=> Amazon.co.uk Hana pH meters My favorite is item 6, which is a pH/TDS/Conductivity meter. It's so easy to use and is almost instant. No messy liquids, except for when you have to calibrate, which is not that often, and no silly color charts to interpret.
Cheers,
PeteA said:what I'd love is one that has a probe that lives in the tank and the display lives in the cupboard but I fear that is completely out of my price range
No mate, you cannot compare the pH readings of the tank to that of the dropchecker. The tank water has unrelated organic acids that corrupt the calculations used in the tables and therefore the pH reading of tank water cannot be used in the tables, however, for this exercise, we assume that in the space of 6-8 hours, those organic acids concentrations won't change too much, so what we're looking for is the change of pH over that period, which we then assume is due to the change in the carbonic acid only, and thus will indicate a change in the CO2 content. The dropchecker water has no other acids. It is completely isolated by a column of air and so the changes that occur within the checker do reflect the absolute values of the waters CO2 content. However, because of the mechanism by which the checker works, it cannot tell us what is happening right now. It is always a few hours behind in it's indication, therefore we cannot use it for this exercise, because the slowness of it's response masks the behavior of the phenomenon we are trying to investigate.GillesF said:Hey Ceg
so if I understand correctly, you double check your DC measurements by testing the pH and comparing that value to those in the pH/KH table? So if your aquarium water has 6,6 pH and 4dKH (from your DC) that would mean 31ppm of CO2, right? In that case, the pH/KH table is reliable because the KH solution is "clean" from other sources that might influence the test (acids etc)?
How accurate is that Hanna meter of yours?
ceg4048 said:No mate, you cannot compare the pH readings of the tank to that of the dropchecker. The tank water has unrelated organic acids that corrupt the calculations used in the tables and therefore the pH reading of tank water cannot be used in the tables, however, for this exercise, we assume that in the space of 6-8 hours, those organic acids concentrations won't change too much, so what we're looking for is the change of pH over that period, which we then assume is due to the change in the carbonic acid only, and thus will indicate a change in the CO2 content. The dropchecker water has no other acids. It is completely isolated by a column of air and so the changes that occur within the checker do reflect the absolute values of the waters CO2 content. However, because of the mechanism by which the checker works, it cannot tell us what is happening right now. It is always a few hours behind in it's indication, therefore we cannot use it for this exercise, because the slowness of it's response masks the behavior of the phenomenon we are trying to investigate.GillesF said:Hey Ceg
so if I understand correctly, you double check your DC measurements by testing the pH and comparing that value to those in the pH/KH table? So if your aquarium water has 6,6 pH and 4dKH (from your DC) that would mean 31ppm of CO2, right? In that case, the pH/KH table is reliable because the KH solution is "clean" from other sources that might influence the test (acids etc)?
How accurate is that Hanna meter of yours?
In this exercise, the instantaneous pH reading of the tank is not being used for determining absolute CO2 PPM. It's only being used to track changes in PPM. Can you understand the difference? BBA is caused by unwanted changes in CO2, so we need a way to see those changes, not a way to measure absolute values. If our assumption is correct - that the tank water acids don't change appreciably in relation to the carbonic acid over that time period - then it illustrates for us a profile of how the CO2 levels change as a function of time. Understanding how the CO2 levels change, in this case, is more valuable than understanding absolute values, because this particular algal bloom is related to the rate of change of CO2.
Hope this makes sense...
Cheers,
OK, well any filamentous algae is definitely related to the absolute value of the CO2 so that means you were low on the injection rate when you switched over. Remember that overdosing only works short term for any of these. When you stop overdosing the injection rate needs to be high enough, the diffusion method needs to be sound enough, and the flow rate and distribution method from the outlet pipes needs to be correct enough in order to keep the plants healthy enough to resist and suppress the blooms.skeletonw00t said:i am using a cynlinder and have been messing with it this week.
Don't know why but hair algae has started to appear. I brought some flourish excel so will overdose for a week to clear up my algae.
Yes, you can. Barr describes CO2 as a narcotic. Plants get hooked on high levels, so when the levels change in a downward direction they start failing even if the absolute value of the new lower level is still what we refer to as "optimal". Take a deep breath, buckle you seat belt and check out the discussions in What causes green spot algae,hair algae and some causes.... and Co2 Fluctuations and BBA and see if any of that makes sense.GillesF said:...Another question: BBA is caused by unstable CO2. But what if the CO2 levels are unstable (due to tweaking) but still optimal (e.g. staying above 30ppm). Is it still possible to have BBA then?
ceg4048 said:So one of the ways to beat BBA is to carefully manage the timing of your CO2 application, so that when plants need a lot they get a lot and when they don't need a lot they don't get a lot. So first of all you need to understand, in that particular tank, just exactly how the CO2 is behaving. We need to know just exactly when there is a lot and when there is not a lot of CO2 in the tank. The only way to get a clue is to take direct pH readings of the tank water at various points in the day. A pH reading every hour, or better yet, every half hour from 2 hours prior to lights on until lights off. The dropchecker is too slow to be useful in this exercise and a pH meter is a handy tool to have.
Generally the CO2 profile in the tank should be something like this:
2 hours prior to lights on - pH at it's maximum daily value => Turn gas ON.
1 hour prior to lights on - ph drops 0.5 units below maximum daily value.
Lights on - pH is at it's lowest daily value, approximately 1 unit below maximum daily value.
1 hour after lights on - pH is slightly above lowest daily value.
The above is an ideal scenario but it's very difficult to achieve. Often, if you are able to drive the CO2 to it's maximum value (pH at it's minimum value) by lights on, the injection rate will continue to drive the pH downwards so that the fish begin to suffer. Maximum CO2 (which causes minimum pH) is required at lights on. A few hours prior to lights OFF, the plants start to drop offline and they do not need as much CO2. Many tanks have trouble in that they do not reach their maximum CO2 until several hours after lights on, and this causes problems, both for plants and fish.