Topping off w/ RO; Diluting nutrients??

[runway1]

I top off with RO about every other day in my 55 gal. Last night my SG was a bit high (1.029) so I emptied about 3-4 gal and replaced it with 5 gal RO and my SG is about 1.026 now.

With topping off of 5%-10% like this, is this diluting my nutrients? Should I supplement when I top off? Thanks all!

 

[seaham358]

It shoud not effect the tank nutrients IMO. My question is how long did you take to lower the SG? dropping 3 points in a short period otf time could cause stress on the fish and inverts.
Check you calcium and alkalinity and adjust them if needed and the other nutrients will be repalced in your next water change.

 

[malkore]

the only thing that evaporates is water, thus top-offs with RO water are the best.

However, what you did wasn't a top-off, you did a small water change and replaced with freshwater because your SG was too high. With true top-offs, SG stays stable. Depending on what you have in the tank, you may need a 2-part calcium/alkalinity system to maintain good levels, but that's really only important if you've got a reef setup, where the corals and inverts need specific level ranges of calcium and alk.
If you just have fish or fish & live rock, calcium and alk aren't crucial parameters to maintain...your normal water changes should keep them at sufficient levels for coraline growth.

 

[sirfishmaster]

are you sure the levels were not elevated because of the evaporation? i keep my levels at 1.026 and if the level of water drops the salt raises...but then toping off brings it back....not sure how your salt levels climed so high unless there was salt in the water you were toping off?


doug