The Conscientious Marine Aquarist: Part 1, Chapter 4 - Water

[ellebelle]

Chapter 4 of The Conscientious Marine Aquarist is all about water quality. Fenner discusses synthetic sea water vs. natural sea water (he advocated synthetic sea water), source water, specific gravity, water changes and maintaining stability. He concludes the chapter with a discussion of what pH is and how we can go about controlling it.

Salt Mixes

Personally, I use synthetic sea salt as do most of the people on this board. Fenner suggests aging it at least 24 hours before doing a water change, but says that one week would be even better. Personally, I think one week is a little much. I usually try to 24 hours. How long do you age your salt mix?

I was also of the opinion that the reason we age salt water for water changes is to make sure that all of the salt is dissolved. Fenner suggests that we do it so that the water is more biologically "ready" to be added to the system, and even suggests putting a cup of your current tank water into the new water. This is an interesting idea - when I do my tank change, I might fill water bottles with half new salt water and half old salt water to try and lessen the shock of the switch on my corals/fish.

Source Water

This section contains one of the more glaring problems I have seen in a book. Fenner says that RO/DIs are not necessary for reef systems if your tap water is of reasonable quality. Personally, I would never EVER start a reef tank with anything other than RO/DI. If you do not start with RO/DI water, it is my opinion that you will forever be battling bad water quality. Period.

Water Changes

Don't be lazy. Just do them. I change my water 1-2x per week (on Wed and Sun). I do 2.5g for a 29g system. I know, having a small system makes water changes a 5 minute undertaking. I think water changes are the solution to many of the poor water quality problems that we see coming up on the board.

Salinity

I found it interesting that Fenner doesn't mention the use of a refractometer to maintain proper salinity. he also mentions that if you are using a hydrometer, that they are calibrated for 60 degrees Farenheit and so you should be aiming to 0.023 to get a real reading of 0.025 in 80 degree water. I THINK that if you get a hydrometer from a source that specializes in salt water, this is not the case. Someone with a refractometer and a hydrometer, can you test to see if the readings come out the same?

Stability and pH

First, I am shocked that Fenner never mentions an auto top off as a means of maintaining stability.

I think Fenner's explanation of what pH is and how alkalinity effects it is very good. All beginning reefers should have a good grasp on how pH and alkalinity are related. That being said, I think that part of the chapter would be more useful if he included a slightly more scientific discussion of WHY all of these things are interrelated and a small troubleshooting guide of how to fix problems.

 

[LeslieS]

I THINK that if you get a hydrometer from a source that specializes in salt water, this is not the case. Someone with a refractometer and a hydrometer, can you test to see if the readings come out the same?

I just tested some water that I am mixing for a water change. At 71 degrees, both the hydrometer and the refractometer read 1.023. (Unfortunately my order of salt does not arrive until tomorrow:banghead

Could we have results from a couple of people?

 

[LeslieS]

I was also of the opinion that the reason we age salt water for water changes is to make sure that all of the salt is dissolved. Fenner suggests that we do it so that the water is more biologically "ready" to be added to the system, and even suggests putting a cup of your current tank water into the new water. This is an interesting idea - when I do my tank change, I might fill water bottles with half new salt water and half old salt water to try and lessen the shock of the switch on my corals/fish.

This is interesting. I have been very careful not to get anything in my water change water as I was afraid of starting a mini cycle in water that wasn't going to be used right away. Is this possible?

 

[Harif87]

Ive never aged my water before, and i get the same readings in my tank than i do in the bucket.

I think the source of the water also plays a major role in our systems water quality. After all if the DEP is adding chlorine and dont mind phosphates thats going to be a big problem for us. I currently use tap and i know that my water quality could be much better than it is now. Ive been trying to get a hold of an RO/DI unit (its been difficult..) because i know the improvents i forsee will become reality and not failed expectations.

One thing im surprised about is Fenner not stressing that the heavier the bioload the quicker your water quality will decline thus demanding more water changes. Overstocking only results in more work.

I was also a little curious why Fenner didnt mention refractometers. Are they relatively new to the hobby?? In any case, what fenner says about hydrometers being calibrated to a certain temperature makes perfect sense. Its impossible to use the same hydrometer for a sample on 60 degrees and another sample of 80 degrees. I know some people who have done some tests on the accuracy of hydrometers by comparing with refractometer results and the differences were significant. Also, salt build-up on the needle over time makes for inaccurate readings, which is why he mentions to wash it with FW after ever use.

You know i dont think Fenner mentioned the ATO so far. I think its something to inquire about.



But i do think Fenner should have delved a little deeper in certain instances. I think that many begginers might not get what he says. I also feel like the only reason why i understand what he is talking about is because i already know what he means and if i were a begginer trying to learn then i would be lost. The guy needs to elaborate on what he is talking about! And i agree that Fenner should have explained the more technical side of water chemistry, but i guess he left it out because he wants it to remain a begginers guide and not make it too complicated.
(I hope the next book we do has to do with the utlra-technical side of the chemistry of our water :p, because if we fluently understand the chemistry of our water then well be able to sense whats wrong with our water before the signs let us know)




Another thing. Fenner keeps mentioning that we should return the salt that has "crept" over our equipment back to our aquarium. As far as i can tell, the salt creep advances because of evaporated water that has splashed over our equipment. So to me it sounds like if we reintroduce the salt to our systems itll just raise the salinity to unwanted levels...

 

[LeslieS]

Another thing. Fenner keeps mentioning that we should return the salt that has "crept" over our equipment back to our aquarium. As far as i can tell, the salt creep advances because of evaporated water that has splashed over our equipment. So to me it sounds like if we reintroduce the salt to our systems itll just raise the salinity to unwanted levels...

This is a great point - I highlighted it and then forgot to mention it. I have actually read other books that say DO NOT reintroduce salt creep back into the tank for the reason you gave above.

 

[digitalreefer]

This is a great point - I highlighted it and then forgot to mention it. I have actually read other books that say DO NOT reintroduce salt creep back into the tank for the reason you gave above.

I tend to disagree... if you replace all of the evaporated water with freshwater, any salt that leaves the system will lower your salinity over time. I get a lot of salt creep because of the way my tank is setup and I find that my salinity will drop over time if I don't get the salt back into the system.

 

[LeslieS]

Another thing. Fenner keeps mentioning that we should return the salt that has "crept" over our equipment back to our aquarium. As far as i can tell, the salt creep advances because of evaporated water that has splashed over our equipment. So to me it sounds like if we reintroduce the salt to our systems itll just raise the salinity to unwanted levels...

I tend to disagree... if you replace all of the evaporated water with freshwater, any salt that leaves the system will lower your salinity over time. I get a lot of salt creep because of the way my tank is setup and I find that my salinity will drop over time if I don't get the salt back into the system.

I guess the answer is to test your salinity. If you tend to decrease - add it back in. If you tend to increase - leave it out.

 

[rfc]

Observations on my 29G w/ 15G sump

* RODI water with instant ocean salt mix. I make it up the night before so it is only ages 13-18 hours. 5 gallons water changes every sunday

* currently having to add 1 gallon a day to make up for evaporation

My salinity is 1.026. I get the same readings with my cheap instant ocean hydrometer and my refractometer.

I need to add buffer (alk) more often than Ca to maintain steady levels

One thing I have always noticed...the tank corals 'perk up' right after a water change.

Regards

RFC

 

[jejton]

There was an informal study written up in Advanced Aquarist ( or something like that ) comparing floating, swing arm hydrometers and refractometers and the conclusion was that they are all pretty precise but accuracty varies from brand to brand ( though there wasnt much of a difference between refractometers and swing arm hydrometers that were properly maintained ).

 

[jejton]

Another thing. Fenner keeps mentioning that we should return the salt that has "crept" over our equipment back to our aquarium. As far as i can tell, the salt creep advances because of evaporated water that has splashed over our equipment. So to me it sounds like if we reintroduce the salt to our systems itll just raise the salinity to unwanted levels...

Well if you add top off fresh water you are raising the volume back to the original amount but since you are not adding salt, then you are in effect diluting the tank. If you add top off water and the salt creep, which was contained in that evaporated water, you are in effect adding the same amount of salt and water that was lost and therefore you are maintaining a stable salinity/.