TDS buildup and removal

[reeformadness]

OK, I have done some calculations and this is what I have come up with. My tap water has TDS around 150. I estimate that adding 1/2 gallon of tap water a day as top off to my 75 for one year has left me with a TDS of 423 in my tank. :eek1: These are rough estimates based on the fact that I have changed my water once since I cured the rock (last week) :eek1:. It was an experiment I was doing, I know it sounds crazy. I have decided to move on. I also used Britta filtered water so TDS may have been a little lower. Let's just assume for my question that my calculations are right (they could very well be wrong).

I just got me a RO/DI filter and the water produced is 0 ppm TDS. If I were to do .25 water changes each week it would take 4 weeks to get to tap water levels and 18 weeks to get below 3 ppm (my goal). If I were to do .50 water changes each week it would take 2 weeks to get to tap water levels and 8 weeks to get to below 3 ppm. OK, sorry about all that but heres my question:

Is doing a 50% water change each week OK? Is 25?. I don't want to shock my system. I have some inverts and a goby. I want to get a hold of my algae problem as quickly as possible, but not at the expense of my tank inhabitants (except the algae of course).

Last question: Would all this even be necessary, or will doing regular water changes and topping off with RO/DI be enough? In other words, will the reduction of TDS alone (as opposed to the daily addition) be enough to stop my algae problem and start making ground.

 

[shag26272]

I wouldnt do a 50% water change , just do regular changes and it should get better, im not really sure how the TDS would add up like you are doing it, test for phosphates, you will probably have some from the tap water which will cause algae outbreaks, you should see it going down after your water changes

 

[reeformadness]

Thanks shag. I see you're from NO. Any good aquarium clubs around? I have never got a positive reading on phosphates and I use a phosban reactor too. Basically, if I were to add top off to my tank every 150 days would be adding the entire volume of my tank. So if I initially had 150 then added the volume of my tank twice it would be around 450 minus my last water change (I think). So would 25% a week be overkill?

 

[jdieck]

A 50% water changes can be a little harsh for your system but can be done if you aereate your mixed water very well for at least 24 hours before the change.
Having said that I do not think it to be necesary to make such large water chnages and 15 to 25% water changes per week will be enough for 4 to 6 weeks and a 10% per week change after that.

The reason is that first; the cycle creates a lot more nutrients than what you could have added with the tap water and during the cycle those get consummed by the algae blooms and nitrifying bacteria population growth. Second, over 90 % of the TDS you are measuring are in fact carbonates, Calcium and Magnesium which are not detrimental to your system and also will get consummed as part of the normal calcification process of corals and coralline algae.

 

[reeformadness]

Thanks. I'm starting to think 25% a week for a while won't be overkill. I do mix my salt a day ahead of time and mix with a powerhead. Aside from fresh salt water being caustic, too many times have I woke up the next morning with my salinity 3-5 ppt more than it was the day before. That is interesting about the TDS mostly being beneficial, I never knew so much was Ca, Mg, and CO3. I don't quite get the first reason you stated. Are you saying a 50% change would cause a die off and therefore an ammonia peak?

 

[shag26272]

reeformadness, look up lareefclub.com, you can get all the local info from there, also if you want mix up your water and every couple of days just change out a little its better to do many smal water changes instead of 1 big one

 

[shag26272]

your livestock might not tolerate that kind of a water change is what he is saying

 

[reeformadness]

Thanks Shag. I'm gonna need alot of salt.

 

[jdieck]

<a href=showthread.php?s=&postid=9195543#post9195543 target=_blank>Originally posted</a> by reeformadness
Thanks. I'm starting to think 25% a week for a while won't be overkill. I do mix my salt a day ahead of time and mix with a powerhead. Aside from fresh salt water being caustic, too many times have I woke up the next morning with my salinity 3-5 ppt more than it was the day before. That is interesting about the TDS mostly being beneficial, I never knew so much was Ca, Mg, and CO3. I don't quite get the first reason you stated. Are you saying a 50% change would cause a die off and therefore an ammonia peak?

You mentioned that you just cycled the rock a week ago, that process generated more nutrients into the water than what the tap water would have added. That is what I was referring to as first.
25% water changes are generally safe, making many small ones will require a lot more changes than less 25% ones. The larger the change the effect on the removal of contaminants is exponential.
As an example:
Six water changes of 5% will remove 0.05+.048+.045+.0.043+.041+.039 = 26.5%
Three 10% water changes will remove 0.1+0.09 + 0.08 = 27.1%
the same 30% change in one shot will remove 30%

 

[aquarius77]

I just got my ro/di unit as well and also a handheld tds meter... I tested my lfs water and nearly had a heart attack, 251 TDS?!?!?
I always do a 25 percent water change on my reef so im thinking i want to try a 60 percent change once i get enough water made and a large enough tub to mix it in.
I think i can get away with that because im always doing 25% water changes the way it is, but if your husbandry is different it could shock your system.

 

[shag26272]

youre testing just the RO water right? not the salt water?

 

[reeformadness]

Sorry, that was confusing how I wrote that. No I cured the rock about a year ago doing water changes until my ammonia spike was over. After that I didn't change the water until last week when I did a 25% water change. So it seems that 25% is probably a good number. Unless the fact that my tank is one year established would make 50% water changes OK. Today at least I will do a 25% since that's all the water I have mixed up.

 

[kelley_mc]

Maybe this makes no sense, but.....

Get yourself a big rubbermaid garbage can or two and place it next to your display. These would need to be big enough to hold all of the water in your tank. Make your saltwater in it and wait a day or two. Be sure to have your parameters as close as possible to your display, ie. temp, sg, ph. Once they are, bag up your critters and drain ALL the water form your display. While you are doing this, float the bags in the rubbermaid containers to keep them warm. Once all the water is out of your display, fill it back up with the water in the rubbermaid containers. Now that your display is full, float and acclimate your critters just as you would if you brought them home from a store.

This may be more stressful than doing it over 18 weeks, BUT it is one stressful event, not a series of them over 18 weeks. Your rock will be fine for the short time it takes to drain and refill the tank and you accomplish your goal very quickly. The costs of a couple cheap heaters, small pumps and garbage cans may end up being cheaper than all the salt you would use doing it another way.

Just a thought...

 

[jdieck]

<a href=showthread.php?s=&postid=9197877#post9197877 target=_blank>Originally posted</a> by reeformadness
Sorry, that was confusing how I wrote that. No I cured the rock about a year ago doing water changes until my ammonia spike was over. After that I didn't change the water until last week when I did a 25% water change. So it seems that 25% is probably a good number. Unless the fact that my tank is one year established would make 50% water changes OK. Today at least I will do a 25% since that's all the water I have mixed up.

Whow! hold on, a year without water changes... go slow, the water is so different in organics, tanins and other compunds to newly prepared water than you will need to go slow. 10% water changes every 4 to 5 day will be the way.
This has nothing to do with the tap water at all or the TDS but with the accumulation of by-products of bio load in the tank over that year.

 

[kelley_mc]

I'm confused.... I missed that part, a year? What are your nitrate levels? I am I wrong to assume that if your nitrates are high and have built up that long, then your LR will be leaching nitrates for a long time?

 

[reeformadness]

Actually my nitrates are only 1-2. I have a very low bioload. I only have 1 fish (rainsford's goby) and a few snails and hermits. I have always had 0 phosphate. It was a stupid experiment since I didn't consider all factors (such as TDS and toxins), but I have a lot of nutrient export. I have a skimmer, lots of LR, use AC, polyfilter, phosban, high flow, etc. I also harvest macro and use a diatom filter after stirring up detritus. But the algae remains. I figure the culprit is probably TDS buildup, but we will see. I just did a 25% change so there is no going back on that. But I will take my time I guess.

 

[jimwat]

Anything that has not been consumed and/or exported from your tap water (which is probably very little if anything), will be in the rocks and sand. I'm not sure how extra water changes will help this. You might be better off getting your tap water tested to find out exactly what is in it that "might" be a problem. Usually the biggest problem (for the tank) is phosphates and silicates, which are consumed pretty quickly (algae).

 

[jdieck]

At this point the main effect of having a system without water changes for a long time is the accumulation of organic matter. In your case Nitrates and Phosphates have not been an issue due to the low bioload that require minimum feedings.
Note that Nitrates and Phosphates get continuously consummed by the algae so their measurement might be skewed toward the low level you are seeing because they get consummed as they get generated.
Water changes will take you a long way into reducing that organic build up which also feeds algae and that unfortunately we are not able to measure within resources available to us.

 

[reeformadness]

Good point, jdieck. I kind of assumed that there are plenty of nutrients in the tank regardless of the test kits due to what you said. I have a diatom filter that does a great job sucking out the detritus so I may set that up soon to expedite things. As for feeding, I never have fed the tank. I figured this would be a bad idea without water changes, and all the species I have in my tank are hair algae eaters and hitchhiking filter feeders. I have ALOT of featherdusters, so I hope I don't end up starving them out to the point that it causes an ammonia spike. Jimwat, I have never tested silicates so that might be worth a shot, although tap water problems should be a thing of the past for me since I got a RO/DI filter.